Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR

Ding, Q. -P.; Meier, W. R.; Cui, J.; Xu, M.; Böhmer, A. E.; Bud’ko, S. L.; Canfield, P. C.; Furukawa, Y.

doi:10.1103/PhysRevLett.121.137204

Title: Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in $CaK ({Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ Revealed by NMR

Abstract

Two ordering states, antiferromagnetism and nematicity, have been observed in most iron-based superconductors (SCs). In contrast to those SCs, the newly discovered SC CaK(Fe_1-xNi_x)₄As₄ exhibits an antiferromagnetic (AFM) state, called hedgehog spin-vortex crystal structure, without nematic order, providing the opportunity for the investigation into the relationship between spin fluctuations and SC without any effects of nematic fluctuations. Our ⁷⁵As nuclear magnetic resonance studies on CaK(Fe_1-xNi_x)₄As₄ (0≤ x ≤ 0.049) revealed that CaKFe₄As₄ is located close to a hidden hedgehog SVC AFM quantum-critical point (QCP). The magnetic QCP without nematicity in CaK(Fe_1-xNi_x)₄As₄ highlights the close connection of spin fluctuations and superconductivity in iron-based SCs. The advantage of stoichiometric composition also makes CaKFe₄As₄ an ideal platform for further detailed investigation of the relationship between magnetic QCP and superconductivity in iron-based SCs without disorder effects.

Authors:

Ding, Q. -P. ^[1]; Meier, W. R. ^[1]; Cui, J. ^[1]; Xu, M. ^[1]; Böhmer, A. E. ^[1]; Bud’ko, S. L. ^[1]; Canfield, P. C. ^[1]; Furukawa, Y. ^[1]

Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)

Publication Date:: 2018-09-26

Research Org.:: Ames Lab., Ames, IA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1477242

Alternate Identifier(s):: OSTI ID: 1473998

Report Number(s):: IS-J-9747
Journal ID: ISSN 0031-9007; PRLTAO

Grant/Contract Number:: AC02-07CH11358; GBMF4411

Resource Type:: Accepted Manuscript

Journal Name:: Physical Review Letters

Additional Journal Information:: Journal Volume: 121; Journal Issue: 13; Journal ID: ISSN 0031-9007

Publisher:: American Physical Society (APS)

Country of Publication:: United States

Language:: English

Subject:: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats


                    Ding, Q. -P., Meier, W. R., Cui, J., Xu, M., Böhmer, A. E., Bud’ko, S. L., Canfield, P. C., and Furukawa, Y. Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR.  United States: N. p., 2018. 
Web.  doi:10.1103/PhysRevLett.121.137204.

Copy to clipboard


                    Ding, Q. -P., Meier, W. R., Cui, J., Xu, M., Böhmer, A. E., Bud’ko, S. L., Canfield, P. C., & Furukawa, Y. Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR.  United States.  https://doi.org/10.1103/PhysRevLett.121.137204

Copy to clipboard


                    Ding, Q. -P., Meier, W. R., Cui, J., Xu, M., Böhmer, A. E., Bud’ko, S. L., Canfield, P. C., and Furukawa, Y. Wed .  
"Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR".  United States.  https://doi.org/10.1103/PhysRevLett.121.137204.  https://www.osti.gov/servlets/purl/1477242.

Copy to clipboard


                    
@article{osti_1477242,

  title        = {Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR},

  author       = {Ding, Q. -P. and Meier, W. R. and Cui, J. and Xu, M. and Böhmer, A. E. and Bud’ko, S. L. and Canfield, P. C. and Furukawa, Y.},

  abstractNote = {Two ordering states, antiferromagnetism and nematicity, have been observed in most iron-based superconductors (SCs). In contrast to those SCs, the newly discovered SC CaK(Fe1-xNix)4As4 exhibits an antiferromagnetic (AFM) state, called hedgehog spin-vortex crystal structure, without nematic order, providing the opportunity for the investigation into the relationship between spin fluctuations and SC without any effects of nematic fluctuations. Our 75As nuclear magnetic resonance studies on CaK(Fe1-xNix)4As4 (0≤ x ≤ 0.049) revealed that CaKFe4As4 is located close to a hidden hedgehog SVC AFM quantum-critical point (QCP). The magnetic QCP without nematicity in CaK(Fe1-xNix)4As4 highlights the close connection of spin fluctuations and superconductivity in iron-based SCs. The advantage of stoichiometric composition also makes CaKFe4As4 an ideal platform for further detailed investigation of the relationship between magnetic QCP and superconductivity in iron-based SCs without disorder effects.},

  doi          = {10.1103/PhysRevLett.121.137204},

  journal      = {Physical Review Letters},

  number       = 13,

  volume       = 121,

  place        = {United States},

  year         = {2018},

  month        = {9}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (Publisher)

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1103/PhysRevLett.121.137204

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 12 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Works referenced in this record:

Nodeless multiband superconductivity in stoichiometric single-crystalline ${CaKFe}_{4} {As}_{4}$
journal, March 2017

Cho, Kyuil; Fente, A.; Teknowijoyo, S.
Physical Review B, Vol. 95, Issue 10
DOI: 10.1103/PhysRevB.95.100502

Spin Susceptibility, Phase Diagram, and Quantum Criticality in the Eelctron-Doped High T _c Superconductor Ba(Fe _{1- x} Co _x ) ₂ As ₂
journal, January 2009

Ning, Fanlong; Ahilan, Kanagasingham; Imai, Takashi
Journal of the Physical Society of Japan, Vol. 78, Issue 1
DOI: 10.1143/JPSJ.78.013711

Anisotropic thermodynamic and transport properties of single-crystalline ${CaKFe}_{4} {As}_{4}$
journal, August 2016

Meier, W. R.; Kong, T.; Kaluarachchi, U. S.
Physical Review B, Vol. 94, Issue 6
DOI: 10.1103/PhysRevB.94.064501

Antiferromagnetic order in ${CaK (Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ and its interplay with superconductivity
journal, June 2018

Kreyssig, A.; Wilde, J. M.; Böhmer, A. E.
Physical Review B, Vol. 97, Issue 22
DOI: 10.1103/PhysRevB.97.224521

Hidden $T$ -Linear Scattering Rate in ${Ba}_{0.6} K_{0.4} {Fe}_{2} {As}_{2}$ Revealed by Optical Spectroscopy
journal, September 2013

Dai, Y. M.; Xu, B.; Shen, B.
Physical Review Letters, Vol. 111, Issue 11
DOI: 10.1103/PhysRevLett.111.117001

Contrasting Spin Dynamics between Underdoped and Overdoped $Ba ({Fe}_{1 - x} {Co}_{x})_{2} {As}_{2}$
journal, January 2010

Ning, F. L.; Ahilan, K.; Imai, T.
Physical Review Letters, Vol. 104, Issue 3
DOI: 10.1103/PhysRevLett.104.037001

Coexistence of Cluster Spin Glass and Superconductivity in $Ba ({Fe}_{1 - x} {Co}_{x})_{2} {As}_{2}$ for $0.060 \leq x \leq 0.071$
journal, November 2013

Dioguardi, A. P.; Crocker, J.; Shockley, A. C.
Physical Review Letters, Vol. 111, Issue 20
DOI: 10.1103/PhysRevLett.111.207201

Enhancement of Superconductivity near a Nematic Quantum Critical Point
journal, March 2015

Lederer, S.; Schattner, Y.; Berg, E.
Physical Review Letters, Vol. 114, Issue 9
DOI: 10.1103/PhysRevLett.114.097001

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor
journal, February 2018

Meier, William R.; Ding, Qing-Ping; Kreyssig, Andreas
npj Quantum Materials, Vol. 3, Issue 1
DOI: 10.1038/s41535-017-0076-x

The Effect of Electron-Electron Interaction on the Nuclear Spin Relaxation in Metals
journal, April 1963

Moriya, Tôru
Journal of the Physical Society of Japan, Vol. 18, Issue 4
DOI: 10.1143/JPSJ.18.516

Superconducting phases of $f$ -electron compounds
journal, November 2009

Pfleiderer, Christian
Reviews of Modern Physics, Vol. 81, Issue 4
DOI: 10.1103/RevModPhys.81.1551

A Quantum Critical Point Lying Beneath the Superconducting Dome in Iron Pnictides
journal, March 2014

Shibauchi, T.; Carrington, A.; Matsuda, Y.
Annual Review of Condensed Matter Physics, Vol. 5, Issue 1
DOI: 10.1146/annurev-conmatphys-031113-133921

The pseudogap: friend or foe of high T _c ?
journal, December 2005

Norman, M. R.; Pines, D.; Kallin, C.
Advances in Physics, Vol. 54, Issue 8
DOI: 10.1080/00018730500459906

Quantum criticality
journal, February 2011

Sachdev, Subir; Keimer, Bernhard
Physics Today, Vol. 64, Issue 2
DOI: 10.1063/1.3554314

New-Structure-Type Fe-Based Superconductors: Ca A Fe ₄ As ₄ ( A = K, Rb, Cs) and Sr A Fe ₄ As ₄ ( A = Rb, Cs)
journal, March 2016

Iyo, Akira; Kawashima, Kenji; Kinjo, Tatsuya
Journal of the American Chemical Society, Vol. 138, Issue 10
DOI: 10.1021/jacs.5b12571

Signature of multigap nodeless superconductivity in ${CaKFe}_{4} {As}_{4}$
journal, April 2017

Biswas, P. K.; Iyo, A.; Yoshida, Y.
Physical Review B, Vol. 95, Issue 14
DOI: 10.1103/PhysRevB.95.140505

NMR study of the new magnetic superconductor $CaK {({Fe}_{0.951} {Ni}_{0.049})}_{4} {As}_{4}$ : Microscopic coexistence of the hedgehog spin-vortex crystal and superconductivity
journal, December 2017

Ding, Q. -P.; Meier, W. R.; Böhmer, A. E.
Physical Review B, Vol. 96, Issue 22
DOI: 10.1103/PhysRevB.96.220510

Short-range cluster spin glass near optimal superconductivity in $Ba {Fe}_{2 - x} {Ni}_{x} {As}_{2}$
journal, July 2014

Lu, Xingye; Tam, David W.; Zhang, Chenglin
Physical Review B, Vol. 90, Issue 2
DOI: 10.1103/PhysRevB.90.024509

What lies beneath the dome?
journal, March 2008

Broun, D. M.
Nature Physics, Vol. 4, Issue 3
DOI: 10.1038/nphys909

Anomalous phonon behavior in superconducting ${CaKFe}_{4} {As}_{4}$ : An optical study
journal, February 2017

Yang, Run; Dai, Yaomin; Xu, Bing
Physical Review B, Vol. 95, Issue 6
DOI: 10.1103/PhysRevB.95.064506

Increasing stripe-type fluctuations in $A {Fe}_{2} {As}_{2}$ ( $A = K$ , Rb, Cs) superconductors probed by ${}^{75}{As}$ NMR spectroscopy
journal, March 2018

Zhang, Z. T.; Dmytriieva, D.; Molatta, S.
Physical Review B, Vol. 97, Issue 11
DOI: 10.1103/PhysRevB.97.115110

Anomalous superconducting state in LiFeAs implied by the ⁷⁵ As Knight shift measurement
journal, April 2013

Baek, S-H; Harnagea, L.; Wurmehl, S.
Journal of Physics: Condensed Matter, Vol. 25, Issue 16
DOI: 10.1088/0953-8984/25/16/162204

FeAs-Based Superconductivity: A Case Study of the Effects of Transition Metal Doping on BaFe ₂ As ₂
journal, August 2010

Canfield, Paul C.; Bud'ko, Sergey L.
Annual Review of Condensed Matter Physics, Vol. 1, Issue 1
DOI: 10.1146/annurev-conmatphys-070909-104041

Spin-Fluctuation-Induced Non-Fermi-Liquid Behavior with Suppressed Superconductivity in ${LiFe}_{1 - x} {Co}_{x} As$
journal, September 2015

Dai, Y. M.; Miao, H.; Xing, L. Y.
Physical Review X, Vol. 5, Issue 3
DOI: 10.1103/PhysRevX.5.031035

Magnetic fluctuations and superconducting properties of ${CaKFe}_{4} {As}_{4}$ studied by ${}^{75}{As}$ NMR
journal, September 2017

Cui, J.; Ding, Q. -P.; Meier, W. R.
Physical Review B, Vol. 96, Issue 10
DOI: 10.1103/PhysRevB.96.104512

Optimization of the crystal growth of the superconductor ${CaKFe}_{4} {As}_{4}$ from solution in the $FeAs − {CaFe}_{2} {As}_{2} − {KFe}_{2} {As}_{2}$ system
journal, June 2017

Meier, W. R.; Kong, T.; Bud'ko, S. L.
Physical Review Materials, Vol. 1, Issue 1
DOI: 10.1103/PhysRevMaterials.1.013401

Antiferromagnetic spin correlations and pseudogaplike behavior in $Ca {({Fe}_{1 - x} {Co}_{x})}_{2} {As}_{2}$ studied by ${}^{75}{As}$ nuclear magnetic resonance and anisotropic resistivity
journal, November 2015

Cui, J.; Roy, B.; Tanatar, M. A.
Physical Review B, Vol. 92, Issue 18
DOI: 10.1103/PhysRevB.92.184504

Superconductivity in iron compounds
journal, December 2011

Stewart, G. R.
Reviews of Modern Physics, Vol. 83, Issue 4
DOI: 10.1103/RevModPhys.83.1589

Muon spin rotation study of magnetism and superconductivity in Ba(Fe $_{1 - x}$ Co $_{x}$ ) $_{2}$ As $_{2}$ single crystals
journal, November 2012

Bernhard, C.; Wang, C. N.; Nuccio, L.
Physical Review B, Vol. 86, Issue 18
DOI: 10.1103/PhysRevB.86.184509

Iron pnictides as a new setting for quantum criticality
journal, March 2009

Dai, J.; Si, Q.; Zhu, J. -X.
Proceedings of the National Academy of Sciences, Vol. 106, Issue 11
DOI: 10.1073/pnas.0900886106

Unconventional Superconductivity and Antiferromagnetic Quantum Critical Behavior in the Isovalent-Doped ${BaFe}_{2} ({As}_{1 - x} P_{x})_{2}$
journal, September 2010

Nakai, Y.; Iye, T.; Kitagawa, S.
Physical Review Letters, Vol. 105, Issue 10
DOI: 10.1103/PhysRevLett.105.107003

Competing order and nature of the pairing state in the iron pnictides
journal, July 2010

Fernandes, Rafael M.; Schmalian, Jörg
Physical Review B, Vol. 82, Issue 1
DOI: 10.1103/PhysRevB.82.014521

Emergent Kondo Lattice Behavior in Iron-Based Superconductors $A {Fe}_{2} {As}_{2}$ ( $A = K$ , Rb, Cs)
journal, April 2016

Wu, Y. P.; Zhao, D.; Wang, A. F.
Physical Review Letters, Vol. 116, Issue 14
DOI: 10.1103/PhysRevLett.116.147001

Gap symmetry and structure of Fe-based superconductors
journal, October 2011

Hirschfeld, P. J.; Korshunov, M. M.; Mazin, I. I.
Reports on Progress in Physics, Vol. 74, Issue 12
DOI: 10.1088/0034-4885/74/12/124508

Enhancement of the Superconducting Gap by Nesting in ${CaKFe}_{4} {As}_{4}$ : A New High Temperature Superconductor
journal, December 2016

Mou, Daixiang; Kong, Tai; Meier, William R.
Physical Review Letters, Vol. 117, Issue 27
DOI: 10.1103/PhysRevLett.117.277001

Quantum criticality in electron-doped BaFe2−xNixAs2
journal, August 2013

Zhou, R.; Li, Z.; Yang, J.
Nature Communications, Vol. 4, Issue 1
DOI: 10.1038/ncomms3265

Ising Nematic Quantum Critical Point in a Metal: A Monte Carlo Study
journal, August 2016

Schattner, Yoni; Lederer, Samuel; Kivelson, Steven A.
Physical Review X, Vol. 6, Issue 3
DOI: 10.1103/PhysRevX.6.031028

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe ₄ As ₄
journal, September 2017

Iida, Kazuki; Ishikado, Motoyuki; Nagai, Yuki
Journal of the Physical Society of Japan, Vol. 86, Issue 9
DOI: 10.7566/JPSJ.86.093703

The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides
journal, October 2010

Johnston, David C.
Advances in Physics, Vol. 59, Issue 6
DOI: 10.1080/00018732.2010.513480

Quantum criticality
journal, January 2005

Coleman, Piers; Schofield, Andrew J.
Nature, Vol. 433, Issue 7023
DOI: 10.1038/nature03279

Superconducting phases of f-electron compounds
text, January 2009

Pfleiderer, C.
arXiv
DOI: 10.48550/arxiv.0905.2625

FeAs-based superconductivity: a case study of the effects of transition metal doping on BaFe2As2
text, January 2010

Canfield, Paul C.; Bud'ko, Sergey L.
arXiv
DOI: 10.48550/arxiv.1002.0858

Competing order and nature of the pairing state in the iron pnictides
text, January 2010

Fernandes, Rafael M.; Schmalian, Jörg
arXiv
DOI: 10.48550/arxiv.1005.2437

Quantum Criticality
text, January 2011

Sachdev, Subir; Keimer, Bernhard
arXiv
DOI: 10.48550/arxiv.1102.4628

Superconductivity in Iron Compounds
text, January 2011

Stewart, G. R.
arXiv
DOI: 10.48550/arxiv.1106.1618

Quantum critical point lying beneath the superconducting dome in iron-pnictides
text, January 2013

Shibauchi, T.; Carrington, A.; Matsuda, Y.
arXiv
DOI: 10.48550/arxiv.1304.6387

Avoided quantum criticality and magnetoelastic coupling in BaFe$_{2-x}$Ni$_{x}$As$_{2}$
text, January 2013

Lu, Xingye; Gretarsson, H.; Zhang, Rui
arXiv
DOI: 10.48550/arxiv.1306.4757

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor
text, January 2017

Meier, W. R.; Ding, Q. -P.; Kreyssig, A.
arXiv
DOI: 10.48550/arxiv.1706.01067

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4
text, January 2017

Iida, K.; Ishikado, M.; Nagai, Y.
arXiv
DOI: 10.48550/arxiv.1708.01006

The pseudogap: friend or foe of high Tc?
text, January 2005

Norman, M. R.; Pines, D.; Kallin, C.
arXiv
DOI: 10.48550/arxiv.cond-mat/0507031

Similar Records in DOE PAGES and OSTI.GOV collections:

Antiferromagnetic order in ${CaK (Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ and its interplay with superconductivity

Journal Article Kreyssig, A. ; Wilde, John M. ; Bohmer, A. E. ; ... - Physical Review B

The magnetic order in CaK(Fe1-xNix)4As4 (1144) single crystals (x=0.051 and 0.033) has been studied by neutron diffraction. We observe magnetic Bragg peaks associated with the same propagation vectors as found for the collinear stripe antiferromagnetic (AFM) order in the related BaFe2As2 (122) compound. The AFM state in 1144 preserves tetragonal symmetry and only a commensurate, noncollinear structure with a hedgehog spin-vortex crystal (SVC) arrangement in the Fe plane and simple AFM stacking along the c direction is consistent with our observations. The SVC order is promoted by the reduced symmetry in the FeAs layer in the 1144 structure. The long-rangemore »« less
Cited by 23
https://doi.org/10.1103/PhysRevB.97.224521

Full Text Available
Antiferromagnetic order and its interplay with superconductivity in CaK(Fe$$_{1-x}$$Mn$$_x$$)₄As₄

Journal Article Wilde, J. M. ; Sapkota, A. ; Ding, Q-P ; ... - Journal of Physics. Condensed Matter

The magnetic order for several compositions of CaK(Femore »« less
https://doi.org/10.1088/1361-648x/ace093

Full Text Available
Pressure-temperature phase diagrams of $CaK ({Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ superconductors

Journal Article Xiang, Li ; Meier, William R. ; Xu, Mingyu ; ... - Physical Review B

In this paper, the pressure dependence of the magnetic and superconducting transitions and that of the superconducting upper critical field are reported formore »« less
Cited by 10
https://doi.org/10.1103/PhysRevB.97.174517

Full Text Available
Robust $s_{\pm}$ pairing in $CaK {({Fe}_{1 - x} {Ni}_{x})}_{4} {As}_{4}$ ( $x = 0$ and 0.05) from the response to electron irradiation

Journal Article Teknowijoyo, S. ; Cho, K. ; Konczykowski, M. ; ... - Physical Review B

Here, controlled pointlike disorder introduced by 2.5-MeV electron irradiation was used to probe the superconducting state of single crystals of CaK(Fe_1–xNi_x)₄As₄ superconductor at x = 0 and 0.05 doping levels. Both compositions show an increase of the residual resistivity and a decrease of the superconducting transition temperature, T_c, at the rate of dT_c/dρ(T_c) ≈ 0.19 K/(μΩcm) for x = 0 and 0.38 K/(μΩcm) for x = 0.05, respectively. In the Ni-doped compound (x = 0.05), the coexisting spin-vortex crystal (SVC) magnetic phase is suppressed at the rate of dT_N/dρ(T_N) ≈ 0.16 K/(μΩcm). The low-temperature variation of London penetration depth ismore »« less
Cited by 14
https://doi.org/10.1103/PhysRevB.97.140508

Full Text Available
Effect of Ni doping on vortex pinning in $CaK {(F e_{1 - x} N i_{x})}_{4} A s_{4}$ single crystals

Journal Article Haberkorn, N. ; Xu, M. ; Meier, W. R. ; ... - Physical Review B

We study the correlation between chemical composition and vortex dynamics in Ni-doped CaK(Fe_1–xNi_x)₄As₄ (x = 0, 0.015, 0.025, 0.03, and 0.05) single crystals by performing measurements of the critical current densities J_c and the flux creep rates S. The magnetic relaxation of all the crystals is well described by the collective creep theory. The samples display a glassy exponent μ within the predictions for vortex bundles in a weak pinning scenario and relatively small characteristic pinning energy (U₀ < 100K). The undoped crystals display modest J_c values at low temperatures and high magnetic fields applied along the c axis. J_c(T)more »« less
Cited by 11
https://doi.org/10.1103/PhysRevB.100.064524

Full Text Available

Similar Records

Title: Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK ( Fe 1 - x Ni x ) 4 As 4 Revealed by NMR

Abstract

Citation Formats

Nodeless multiband superconductivity in stoichiometric single-crystalline CaKFe 4 As 4 journal, March 2017

Spin Susceptibility, Phase Diagram, and Quantum Criticality in the Eelctron-Doped High T c Superconductor Ba(Fe 1- x Co x ) 2 As 2 journal, January 2009

Anisotropic thermodynamic and transport properties of single-crystalline CaKFe 4 As 4 journal, August 2016

Antiferromagnetic order in CaK ( Fe 1 − x Ni x ) 4 As 4 and its interplay with superconductivity journal, June 2018

Hidden T -Linear Scattering Rate in Ba 0.6 K 0.4 Fe 2 As 2 Revealed by Optical Spectroscopy journal, September 2013

Contrasting Spin Dynamics between Underdoped and Overdoped Ba ( Fe 1 − x Co x ) 2 As 2 journal, January 2010

Coexistence of Cluster Spin Glass and Superconductivity in Ba ( Fe 1 − x Co x ) 2 As 2 for 0.060 ≤ x ≤ 0.071 journal, November 2013

Enhancement of Superconductivity near a Nematic Quantum Critical Point journal, March 2015

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor journal, February 2018

The Effect of Electron-Electron Interaction on the Nuclear Spin Relaxation in Metals journal, April 1963

Superconducting phases of f -electron compounds journal, November 2009

A Quantum Critical Point Lying Beneath the Superconducting Dome in Iron Pnictides journal, March 2014

The pseudogap: friend or foe of high T c ? journal, December 2005

Quantum criticality journal, February 2011

New-Structure-Type Fe-Based Superconductors: Ca A Fe 4 As 4 ( A = K, Rb, Cs) and Sr A Fe 4 As 4 ( A = Rb, Cs) journal, March 2016

Signature of multigap nodeless superconductivity in CaKFe 4 As 4 journal, April 2017

NMR study of the new magnetic superconductor CaK ( Fe 0.951 Ni 0.049 ) 4 As 4 : Microscopic coexistence of the hedgehog spin-vortex crystal and superconductivity journal, December 2017

Short-range cluster spin glass near optimal superconductivity in Ba Fe 2 − x Ni x As 2 journal, July 2014

What lies beneath the dome? journal, March 2008

Anomalous phonon behavior in superconducting CaKFe 4 As 4 : An optical study journal, February 2017

Increasing stripe-type fluctuations in A Fe 2 As 2 ( A = K , Rb, Cs) superconductors probed by As 75 NMR spectroscopy journal, March 2018

Anomalous superconducting state in LiFeAs implied by the 75 As Knight shift measurement journal, April 2013

FeAs-Based Superconductivity: A Case Study of the Effects of Transition Metal Doping on BaFe 2 As 2 journal, August 2010

Spin-Fluctuation-Induced Non-Fermi-Liquid Behavior with Suppressed Superconductivity in LiFe 1 − x Co x As journal, September 2015

Magnetic fluctuations and superconducting properties of CaKFe 4 As 4 studied by As 75 NMR journal, September 2017

Optimization of the crystal growth of the superconductor CaKFe 4 As 4 from solution in the FeAs − CaFe 2 As 2 − KFe 2 As 2 system journal, June 2017

Antiferromagnetic spin correlations and pseudogaplike behavior in Ca ( Fe 1 − x Co x ) 2 As 2 studied by As 75 nuclear magnetic resonance and anisotropic resistivity journal, November 2015

Superconductivity in iron compounds journal, December 2011

Muon spin rotation study of magnetism and superconductivity in Ba(Fe 1 − x Co x ) 2 As 2 single crystals journal, November 2012

Iron pnictides as a new setting for quantum criticality journal, March 2009

Unconventional Superconductivity and Antiferromagnetic Quantum Critical Behavior in the Isovalent-Doped BaFe 2 ( As 1 − x P x ) 2 journal, September 2010

Competing order and nature of the pairing state in the iron pnictides journal, July 2010

Emergent Kondo Lattice Behavior in Iron-Based Superconductors A Fe 2 As 2 ( A = K , Rb, Cs) journal, April 2016

Gap symmetry and structure of Fe-based superconductors journal, October 2011

Enhancement of the Superconducting Gap by Nesting in CaKFe 4 As 4 : A New High Temperature Superconductor journal, December 2016

Quantum criticality in electron-doped BaFe2−xNixAs2 journal, August 2013

Ising Nematic Quantum Critical Point in a Metal: A Monte Carlo Study journal, August 2016

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe 4 As 4 journal, September 2017

The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides journal, October 2010

Quantum criticality journal, January 2005

Superconducting phases of f-electron compounds text, January 2009

FeAs-based superconductivity: a case study of the effects of transition metal doping on BaFe2As2 text, January 2010

Competing order and nature of the pairing state in the iron pnictides text, January 2010

Quantum Criticality text, January 2011

Superconductivity in Iron Compounds text, January 2011

Quantum critical point lying beneath the superconducting dome in iron-pnictides text, January 2013

Avoided quantum criticality and magnetoelastic coupling in BaFe$_{2-x}$Ni$_{x}$As$_{2}$ text, January 2013

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor text, January 2017

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4 text, January 2017

The pseudogap: friend or foe of high Tc? text, January 2005

Title: Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in $CaK ({Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ Revealed by NMR

Nodeless multiband superconductivity in stoichiometric single-crystalline ${CaKFe}_{4} {As}_{4}$
journal, March 2017

Spin Susceptibility, Phase Diagram, and Quantum Criticality in the Eelctron-Doped High T _c Superconductor Ba(Fe _{1- x} Co _x ) ₂ As ₂
journal, January 2009

Anisotropic thermodynamic and transport properties of single-crystalline ${CaKFe}_{4} {As}_{4}$
journal, August 2016

Antiferromagnetic order in ${CaK (Fe}_{1 - x} {Ni}_{x})_{4} {As}_{4}$ and its interplay with superconductivity
journal, June 2018

Hidden $T$ -Linear Scattering Rate in ${Ba}_{0.6} K_{0.4} {Fe}_{2} {As}_{2}$ Revealed by Optical Spectroscopy
journal, September 2013

Contrasting Spin Dynamics between Underdoped and Overdoped $Ba ({Fe}_{1 - x} {Co}_{x})_{2} {As}_{2}$
journal, January 2010

Coexistence of Cluster Spin Glass and Superconductivity in $Ba ({Fe}_{1 - x} {Co}_{x})_{2} {As}_{2}$ for $0.060 \leq x \leq 0.071$
journal, November 2013

Enhancement of Superconductivity near a Nematic Quantum Critical Point
journal, March 2015

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor
journal, February 2018

The Effect of Electron-Electron Interaction on the Nuclear Spin Relaxation in Metals
journal, April 1963

Superconducting phases of $f$ -electron compounds
journal, November 2009

A Quantum Critical Point Lying Beneath the Superconducting Dome in Iron Pnictides
journal, March 2014

The pseudogap: friend or foe of high T _c ?
journal, December 2005

Quantum criticality
journal, February 2011

New-Structure-Type Fe-Based Superconductors: Ca A Fe ₄ As ₄ ( A = K, Rb, Cs) and Sr A Fe ₄ As ₄ ( A = Rb, Cs)
journal, March 2016

Signature of multigap nodeless superconductivity in ${CaKFe}_{4} {As}_{4}$
journal, April 2017

NMR study of the new magnetic superconductor $CaK {({Fe}_{0.951} {Ni}_{0.049})}_{4} {As}_{4}$ : Microscopic coexistence of the hedgehog spin-vortex crystal and superconductivity
journal, December 2017

Short-range cluster spin glass near optimal superconductivity in $Ba {Fe}_{2 - x} {Ni}_{x} {As}_{2}$
journal, July 2014

What lies beneath the dome?
journal, March 2008

Anomalous phonon behavior in superconducting ${CaKFe}_{4} {As}_{4}$ : An optical study
journal, February 2017

Increasing stripe-type fluctuations in $A {Fe}_{2} {As}_{2}$ ( $A = K$ , Rb, Cs) superconductors probed by ${}^{75}{As}$ NMR spectroscopy
journal, March 2018

Anomalous superconducting state in LiFeAs implied by the ⁷⁵ As Knight shift measurement
journal, April 2013

FeAs-Based Superconductivity: A Case Study of the Effects of Transition Metal Doping on BaFe ₂ As ₂
journal, August 2010

Spin-Fluctuation-Induced Non-Fermi-Liquid Behavior with Suppressed Superconductivity in ${LiFe}_{1 - x} {Co}_{x} As$
journal, September 2015

Magnetic fluctuations and superconducting properties of ${CaKFe}_{4} {As}_{4}$ studied by ${}^{75}{As}$ NMR
journal, September 2017

Optimization of the crystal growth of the superconductor ${CaKFe}_{4} {As}_{4}$ from solution in the $FeAs − {CaFe}_{2} {As}_{2} − {KFe}_{2} {As}_{2}$ system
journal, June 2017

Antiferromagnetic spin correlations and pseudogaplike behavior in $Ca {({Fe}_{1 - x} {Co}_{x})}_{2} {As}_{2}$ studied by ${}^{75}{As}$ nuclear magnetic resonance and anisotropic resistivity
journal, November 2015

Superconductivity in iron compounds
journal, December 2011

Muon spin rotation study of magnetism and superconductivity in Ba(Fe $_{1 - x}$ Co $_{x}$ ) $_{2}$ As $_{2}$ single crystals
journal, November 2012

Iron pnictides as a new setting for quantum criticality
journal, March 2009

Unconventional Superconductivity and Antiferromagnetic Quantum Critical Behavior in the Isovalent-Doped ${BaFe}_{2} ({As}_{1 - x} P_{x})_{2}$
journal, September 2010

Competing order and nature of the pairing state in the iron pnictides
journal, July 2010

Emergent Kondo Lattice Behavior in Iron-Based Superconductors $A {Fe}_{2} {As}_{2}$ ( $A = K$ , Rb, Cs)
journal, April 2016

Gap symmetry and structure of Fe-based superconductors
journal, October 2011

Enhancement of the Superconducting Gap by Nesting in ${CaKFe}_{4} {As}_{4}$ : A New High Temperature Superconductor
journal, December 2016

Quantum criticality in electron-doped BaFe2−xNixAs2
journal, August 2013

Ising Nematic Quantum Critical Point in a Metal: A Monte Carlo Study
journal, August 2016

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe ₄ As ₄
journal, September 2017

The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides
journal, October 2010

Quantum criticality
journal, January 2005

Superconducting phases of f-electron compounds
text, January 2009

FeAs-based superconductivity: a case study of the effects of transition metal doping on BaFe2As2
text, January 2010

Competing order and nature of the pairing state in the iron pnictides
text, January 2010

Quantum Criticality
text, January 2011

Superconductivity in Iron Compounds
text, January 2011

Quantum critical point lying beneath the superconducting dome in iron-pnictides
text, January 2013

Avoided quantum criticality and magnetoelastic coupling in BaFe$_{2-x}$Ni$_{x}$As$_{2}$
text, January 2013

Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor
text, January 2017

Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4
text, January 2017

The pseudogap: friend or foe of high Tc?
text, January 2005