Anomalous phonon behavior in superconducting CaKFe4As4: An optical study

Yang, Run; Dai, Yaomin; Xu, Bing; Zhang, Wei; Qiu, Ziyang; Sui, Qiangtao; Homes, Christopher C.; Qiu, Xianggang

doi:10.1103/PhysRevB.95.064506

Title: Anomalous phonon behavior in superconducting ${CaKFe}_{4} {As}_{4}$ : An optical study

Abstract

Here, the temperature dependence of ab-plane optical conductivity of CaKFe₄As₄ has been measured below and above its superconducting transition temperature T_c≃35.5 K. In the normal state, analysis with the two-Drude model reveals a T-linear scattering rate for the coherent response, which suggests strong spin-fluctuation scattering. Below the superconducting transition, the optical conductivity below 120 cm^–1 vanishes, indicating nodeless gap(s). The Mattis-Bardeen fitting in the superconducting state gives two gaps of Δ₁ ≃ 9 meV and Δ₂ ≃ 14 meV, in good agreement with recent angle-resolved photoemission spectroscopy (ARPES) results. In addition, around 255 cm^–1, we observe two different infrared-active Fe-As modes with obvious asymmetric lineshape, originating from strong coupling between lattice vibrations and spin or charge excitations. Considering a moderate Hund's rule coupling determined from spectral weight analysis, we propose that the strong fluctuations induced by the coupling between itinerant carriers and local moments may affect the phonon mode, and the electron-phonon coupling through the spin channel is likely to play an important role in the unconventional pairing in iron-based superconductors.

Authors:

Yang, Run ^[1]; Dai, Yaomin ^[2]; Xu, Bing ^[3]; Zhang, Wei ^[4]; Qiu, Ziyang ^[4]; Sui, Qiangtao ^[4]; Homes, Christopher C. ^[2]; Qiu, Xianggang ^[5]

Chinese Academy of Sciences (CAS), Beijing (China); Brookhaven National Lab. (BNL), Upton, NY (United States)
Brookhaven National Lab. (BNL), Upton, NY (United States)
Center for High Pressure Science and Technology Advanced Research, Beijing (China)
Chinese Academy of Sciences (CAS), Beijing (China)
Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

Publication Date:: Wed Feb 08 00:00:00 EST 2017

Research Org.:: Brookhaven National Lab. (BNL), Upton, NY (United States)

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

OSTI Identifier:: 1345727

Alternate Identifier(s):: OSTI ID: 1343337

Report Number(s):: BNL-113510-2017-JA
Journal ID: ISSN 2469-9950; PRBMDO; R&D Project: PO016; KC0202020; TRN: US1700873

Grant/Contract Number:: SC00112704; SC0012704

Resource Type:: Accepted Manuscript

Journal Name:: Physical Review B

Additional Journal Information:: Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 2469-9950

Publisher:: American Physical Society (APS)

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats


                    Yang, Run, Dai, Yaomin, Xu, Bing, Zhang, Wei, Qiu, Ziyang, Sui, Qiangtao, Homes, Christopher C., and Qiu, Xianggang. Anomalous phonon behavior in superconducting CaKFe4As4: An optical study.  United States: N. p., 2017. 
Web.  doi:10.1103/PhysRevB.95.064506.

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                    Yang, Run, Dai, Yaomin, Xu, Bing, Zhang, Wei, Qiu, Ziyang, Sui, Qiangtao, Homes, Christopher C., & Qiu, Xianggang. Anomalous phonon behavior in superconducting CaKFe4As4: An optical study.  United States.  https://doi.org/10.1103/PhysRevB.95.064506

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                    Yang, Run, Dai, Yaomin, Xu, Bing, Zhang, Wei, Qiu, Ziyang, Sui, Qiangtao, Homes, Christopher C., and Qiu, Xianggang. Wed .  
"Anomalous phonon behavior in superconducting CaKFe4As4: An optical study".  United States.  https://doi.org/10.1103/PhysRevB.95.064506.  https://www.osti.gov/servlets/purl/1345727.

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@article{osti_1345727,

  title        = {Anomalous phonon behavior in superconducting CaKFe4As4: An optical study},

  author       = {Yang, Run and Dai, Yaomin and Xu, Bing and Zhang, Wei and Qiu, Ziyang and Sui, Qiangtao and Homes, Christopher C. and Qiu, Xianggang},

  abstractNote = {Here, the temperature dependence of ab-plane optical conductivity of CaKFe4As4 has been measured below and above its superconducting transition temperature Tc≃35.5 K. In the normal state, analysis with the two-Drude model reveals a T-linear scattering rate for the coherent response, which suggests strong spin-fluctuation scattering. Below the superconducting transition, the optical conductivity below 120 cm–1 vanishes, indicating nodeless gap(s). The Mattis-Bardeen fitting in the superconducting state gives two gaps of Δ1 ≃ 9 meV and Δ2 ≃ 14 meV, in good agreement with recent angle-resolved photoemission spectroscopy (ARPES) results. In addition, around 255 cm–1, we observe two different infrared-active Fe-As modes with obvious asymmetric lineshape, originating from strong coupling between lattice vibrations and spin or charge excitations. Considering a moderate Hund's rule coupling determined from spectral weight analysis, we propose that the strong fluctuations induced by the coupling between itinerant carriers and local moments may affect the phonon mode, and the electron-phonon coupling through the spin channel is likely to play an important role in the unconventional pairing in iron-based superconductors.},

  doi          = {10.1103/PhysRevB.95.064506},

  journal      = {Physical Review B},

  number       = 6,

  volume       = 95,

  place        = {United States},

  year         = {Wed Feb 08 00:00:00 EST 2017},

  month        = {Wed Feb 08 00:00:00 EST 2017}

}

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Works referencing / citing this record:

Odd and Even Modes of Neutron Spin Resonance in the Bilayer Iron-Based Superconductor ${CaKFe}_{4} {As}_{4}$
journal, June 2018

Xie, Tao; Wei, Yuan; Gong, Dongliang
Physical Review Letters, Vol. 120, Issue 26
DOI: 10.1103/physrevlett.120.267003

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Title: Anomalous phonon behavior in superconducting CaKFe 4 As 4 : An optical study

Abstract

Citation Formats

Unconventional superconductivity in Ba0.6K0.4Fe2As2 from inelastic neutron scattering journal, December 2008

Itinerancy-Enhanced Quantum Fluctuation of Magnetic Moments in Iron-Based Superconductors journal, September 2015

Gate Tunable Infrared Phonon Anomalies in Bilayer Graphene journal, September 2009

High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopy journal, July 2012

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

Iron-based high transition temperature superconductors journal, July 2014

Magnetism and charge dynamics in iron pnictides journal, February 2011

Unconventional Superconductivity with a Sign Reversal in the Order Parameter of LaFeAsO 1 − x F x journal, July 2008

FeTe 0.55 Se 0.45 : A multiband superconductor in the clean and dirty limit journal, April 2015

Orbital fluctuation theory in iron pnictides: Effects of As-Fe-As bond angle, isotope substitution, and Z 2 -orbital pocket on superconductivity journal, October 2010

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

Spin-phonon coupling and effect of pressure in the superconductor LiFeAs: Lattice dynamics from first-principles calculations journal, July 2010

Magnetic order close to superconductivity in the iron-based layered LaO1-xF x FeAs systems journal, May 2008

Effect of Pnictogen Height on Spin Waves in Iron Pnictides journal, May 2014

Microscopic origin of magnetism and magnetic interactions in ferropnictides journal, June 2009

Optical study of the antiferromagnetic ordered state in electron-overdoped Ca 0.77 Nd 0.23 FeAs 2 journal, June 2016

Plain s-wave superconductivity in single-layer FeSe on SrTiO3 probed by scanning tunnelling microscopy journal, August 2015

Technique for measuring the reflectance of irregular, submillimeter-sized samples journal, January 1993

Anomalous phonon redshift in K-doped BaFe 2 As 2 iron pnictides journal, March 2015

Probing the Superconducting Energy Gap from Infrared Spectroscopy on a Ba 0.6 K 0.4 Fe 2 As 2 Single Crystal with T c = 37 K journal, September 2008

Phonon anomalies in some iron telluride materials journal, March 2016

Effects of Configuration Interaction on Intensities and Phase Shifts journal, December 1961

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

Strong anharmonicity and spin-phonon coupling in the quasi-two-dimensional quantum spin system Sr 1 − x Ba x Cu 2 ( BO 3 ) 2 journal, September 2003

Orbital fluctuation theory in iron-based superconductors: -wave superconductivity, structure transition, and impurity-induced nematic order journal, April 2012

Optical conductivity of Ba 0.6 K 0.4 Fe 2 As 2 : The effect of in-plane and out-of-plane doping in the superconducting gap journal, November 2013

Observation of a Van Hove singularity and implication for strong-coupling induced Cooper pairing in KFe 2 As 2 journal, October 2015

Optical investigations of the normal and superconducting states reveal two electronic subsystems in iron pnictides journal, March 2010

Anharmonic Decay of Optical Phonons journal, August 1966

Orbital character and electron correlation effects on two- and three-dimensional Fermi surfaces in KFe2As2 revealed by angle-resolved photoemission spectroscopy journal, April 2014

Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides journal, May 2013

Phonon splitting and anomalous enhancement of infrared-active modes in BaFe 2 As 2 journal, August 2011

A large iron isotope effect in SmFeAsO1 - xF x and Ba1 - xK x Fe2As2 journal, May 2009

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

Evolution of the 251 cm −1 infrared phonon mode with temperature in Ba 0.6 K 0.4 Fe 2 As 2 journal, July 2012

Infrared spectra of the low-dimensional quantum magnet SrCu 2 ( BO 3 ) 2 : Measurements and ab initio calculations journal, March 2009

Superconductivity at 43 K in an iron-based layered compound LaO1-xFxFeAs journal, April 2008

Orbital-Fluctuation-Mediated Superconductivity in Iron Pnictides: Analysis of the Five-Orbital Hubbard-Holstein Model journal, April 2010

Surface electronic structure and evidence of plain s -wave superconductivity in ( L i 0.8 F e 0.2 ) OHFeSe journal, October 2016

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Title: Anomalous phonon behavior in superconducting ${CaKFe}_{4} {As}_{4}$ : An optical study

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journal, December 2008

Itinerancy-Enhanced Quantum Fluctuation of Magnetic Moments in Iron-Based Superconductors
journal, September 2015

Gate Tunable Infrared Phonon Anomalies in Bilayer Graphene
journal, September 2009

High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopy
journal, July 2012

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

Iron-based high transition temperature superconductors
journal, July 2014

Magnetism and charge dynamics in iron pnictides
journal, February 2011

Unconventional Superconductivity with a Sign Reversal in the Order Parameter of ${LaFeAsO}_{1 - x} F_{x}$
journal, July 2008

${FeTe}_{0.55} {Se}_{0.45}$ : A multiband superconductor in the clean and dirty limit
journal, April 2015

Orbital fluctuation theory in iron pnictides: Effects of As-Fe-As bond angle, isotope substitution, and $Z^{2}$ -orbital pocket on superconductivity
journal, October 2010

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

Spin-phonon coupling and effect of pressure in the superconductor LiFeAs: Lattice dynamics from first-principles calculations
journal, July 2010

Magnetic order close to superconductivity in the iron-based layered LaO1-xF x FeAs systems
journal, May 2008

Effect of Pnictogen Height on Spin Waves in Iron Pnictides
journal, May 2014

Microscopic origin of magnetism and magnetic interactions in ferropnictides
journal, June 2009

Optical study of the antiferromagnetic ordered state in electron-overdoped ${Ca}_{0.77} {Nd}_{0.23} {FeAs}_{2}$
journal, June 2016

Plain s-wave superconductivity in single-layer FeSe on SrTiO3 probed by scanning tunnelling microscopy
journal, August 2015

Technique for measuring the reflectance of irregular, submillimeter-sized samples
journal, January 1993

Anomalous phonon redshift in K-doped ${BaFe}_{2} {As}_{2}$ iron pnictides
journal, March 2015

Probing the Superconducting Energy Gap from Infrared Spectroscopy on a ${Ba}_{0.6} K_{0.4} {Fe}_{2} {As}_{2}$ Single Crystal with $T_{c} = 37 K$
journal, September 2008

Phonon anomalies in some iron telluride materials
journal, March 2016

Effects of Configuration Interaction on Intensities and Phase Shifts
journal, December 1961

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

Strong anharmonicity and spin-phonon coupling in the quasi-two-dimensional quantum spin system ${Sr}_{1 - x} {Ba}_{x} {Cu}_{2} ({BO}_{3})_{2}$
journal, September 2003

Orbital fluctuation theory in iron-based superconductors: -wave superconductivity, structure transition, and impurity-induced nematic order
journal, April 2012

Optical conductivity of Ba _0.6 K _0.4 Fe ₂ As ₂ : The effect of in-plane and out-of-plane doping in the superconducting gap
journal, November 2013

Observation of a Van Hove singularity and implication for strong-coupling induced Cooper pairing in ${KFe}_{2} {As}_{2}$
journal, October 2015

Optical investigations of the normal and superconducting states reveal two electronic subsystems in iron pnictides
journal, March 2010

Anharmonic Decay of Optical Phonons
journal, August 1966

Orbital character and electron correlation effects on two- and three-dimensional Fermi surfaces in KFe2As2 revealed by angle-resolved photoemission spectroscopy
journal, April 2014

Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides
journal, May 2013

Phonon splitting and anomalous enhancement of infrared-active modes in BaFe $_{2}$ As $_{2}$
journal, August 2011

A large iron isotope effect in SmFeAsO1 - xF x and Ba1 - xK x Fe2As2
journal, May 2009

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

Evolution of the 251 cm ⁻¹ infrared phonon mode with temperature in Ba _0.6 K _0.4 Fe ₂ As ₂
journal, July 2012

Infrared spectra of the low-dimensional quantum magnet ${SrCu}_{2} {({BO}_{3})}_{2}$ : Measurements and ab initio calculations
journal, March 2009

Superconductivity at 43 K in an iron-based layered compound LaO1-xFxFeAs
journal, April 2008

Orbital-Fluctuation-Mediated Superconductivity in Iron Pnictides: Analysis of the Five-Orbital Hubbard-Holstein Model
journal, April 2010

Surface electronic structure and evidence of plain $s$ -wave superconductivity in $(L i_{0.8} F e_{0.2}) OHFeSe$
journal, October 2016

Raman spectroscopy of $R FeAsO$ ( $R$ =Sm, La)
journal, June 2008

Odd and Even Modes of Neutron Spin Resonance in the Bilayer Iron-Based Superconductor ${CaKFe}_{4} {As}_{4}$
journal, June 2018