DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal KxFe2-ySe2

Abstract

Here, we report how the superconducting phase forms in pseudo-single-crystal KxFe2-ySe2. In situ scanning electron microscopy (SEM) observation reveals that, as an order-disorder transition occurs, on cooling, most of the high-temperature iron-vacancy-disordered phase gradually changes into the iron-vacancy-ordered phase whereas a small quantity of the high-temperature phase retains its structure and aggregates to the stripes with more iron concentration but less potassium concentration compared to the iron-vacancy-ordered phase. The stripes that are generally recognized as the superconducting phase are actually formed as a remnant of the high-temperature phase with a compositional change after an “imperfect” order-disorder transition. It should be emphasized that the phase separation in pseudo-single-crystal KxFe2-ySe2 is caused by the iron-vacancy order-disorder transition. The shrinkage of the high-temperature phase and the expansion of the newly created iron-vacancy-ordered phase during the phase separation rule out the mechanism of spinodal decomposition proposed in an early report [Wang et al, Phys. Rev. B 91, 064513 (2015)]. Since the formation of the superconducting phase relies on the occurrence of the iron-vacancy order-disorder transition, it is impossible to synthesize a pure superconducting phase by a conventional solid state reaction or melt growth. By focused ion beam-scanning electron microscopy, we further demonstrate that themore » superconducting phase forms a contiguous three-dimensional architecture composed of parallelepipeds that have a coherent orientation relationship with the iron-vacancy-ordered phase.« less

Authors:
 [1];  [1];  [2];  [3];  [4];  [5];  [2]
  1. Ames Lab., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  3. Carl Zeiss Microscopy, LLC, Peabody, MA (United States). Ion Microscopy Innovation Center (IMIC)
  4. Carl Zeiss Microscopy, LLC, Thornwood, NY (United States)
  5. Oxford Instruments America, Inc., Concord, MA (United States)
Publication Date:
Research Org.:
Ames Lab., Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1249341
Alternate Identifier(s):
OSTI ID: 1237792
Report Number(s):
IS-J-8950
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
AC02-07CH11358
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; 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

Liu, Yong, Xing, Qingfeng, Straszheim, Warren E., Marshman, Jeff, Pedersen, Pal, McLaughlin, Richard, and Lograsso, Thomas A.. Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal KxFe2-ySe2. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.93.064509.
Liu, Yong, Xing, Qingfeng, Straszheim, Warren E., Marshman, Jeff, Pedersen, Pal, McLaughlin, Richard, & Lograsso, Thomas A.. Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal KxFe2-ySe2. United States. https://doi.org/10.1103/PhysRevB.93.064509
Liu, Yong, Xing, Qingfeng, Straszheim, Warren E., Marshman, Jeff, Pedersen, Pal, McLaughlin, Richard, and Lograsso, Thomas A.. Thu . "Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal KxFe2-ySe2". United States. https://doi.org/10.1103/PhysRevB.93.064509. https://www.osti.gov/servlets/purl/1249341.
@article{osti_1249341,
title = {Formation mechanism of superconducting phase and its three-dimensional architecture in pseudo-single-crystal KxFe2-ySe2},
author = {Liu, Yong and Xing, Qingfeng and Straszheim, Warren E. and Marshman, Jeff and Pedersen, Pal and McLaughlin, Richard and Lograsso, Thomas A.},
abstractNote = {Here, we report how the superconducting phase forms in pseudo-single-crystal KxFe2-ySe2. In situ scanning electron microscopy (SEM) observation reveals that, as an order-disorder transition occurs, on cooling, most of the high-temperature iron-vacancy-disordered phase gradually changes into the iron-vacancy-ordered phase whereas a small quantity of the high-temperature phase retains its structure and aggregates to the stripes with more iron concentration but less potassium concentration compared to the iron-vacancy-ordered phase. The stripes that are generally recognized as the superconducting phase are actually formed as a remnant of the high-temperature phase with a compositional change after an “imperfect” order-disorder transition. It should be emphasized that the phase separation in pseudo-single-crystal KxFe2-ySe2 is caused by the iron-vacancy order-disorder transition. The shrinkage of the high-temperature phase and the expansion of the newly created iron-vacancy-ordered phase during the phase separation rule out the mechanism of spinodal decomposition proposed in an early report [Wang et al, Phys. Rev. B 91, 064513 (2015)]. Since the formation of the superconducting phase relies on the occurrence of the iron-vacancy order-disorder transition, it is impossible to synthesize a pure superconducting phase by a conventional solid state reaction or melt growth. By focused ion beam-scanning electron microscopy, we further demonstrate that the superconducting phase forms a contiguous three-dimensional architecture composed of parallelepipeds that have a coherent orientation relationship with the iron-vacancy-ordered phase.},
doi = {10.1103/PhysRevB.93.064509},
journal = {Physical Review B},
number = 6,
volume = 93,
place = {United States},
year = {Thu Feb 11 00:00:00 EST 2016},
month = {Thu Feb 11 00:00:00 EST 2016}
}

Journal Article:

Citation Metrics:
Cited by: 16 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Superconductivity in the iron selenide K x Fe 2 Se 2 ( 0 x 1.0 )
journal, November 2010


Microstructural analysis of phase separation in iron chalcogenide superconductors
journal, July 2012


Colloquium : The unexpected properties of alkali metal iron selenide superconductors
journal, May 2013


Structure, magnetic order and excitations in the 245 family of Fe-based superconductors
journal, November 2014


Nodeless superconducting gap in AxFe2Se2 (A=K,Cs) revealed by angle-resolved photoemission spectroscopy
journal, February 2011

  • Zhang, Y.; Yang, L. X.; Xu, M.
  • Nature Materials, Vol. 10, Issue 4
  • DOI: 10.1038/nmat2981

d -wave pairing from spin fluctuations in the K x Fe 2 y Se 2 superconductors
journal, March 2011


Emergence of fully gapped s + + -wave and nodal d -wave states mediated by orbital and spin fluctuations in a ten-orbital model of KFe 2 Se 2
journal, April 2011


Archimedean solidlike superconducting framework in phase-separated K 0.8 F e 1.6 + x S e 2 ( 0 x 0.15 )
journal, February 2015


Disordered Fe vacancies and superconductivity in potassium-intercalated iron selenide (K 2− x Fe 4+ y Se 5 )
journal, July 2015


CASINO V2.42—A Fast and Easy-to-use Modeling Tool for Scanning Electron Microscopy and Microanalysis Users
journal, January 2007

  • Drouin, Dominique; Couture, Alexandre Réal; Joly, Dany
  • Scanning, Vol. 29, Issue 3
  • DOI: 10.1002/sca.20000

Intrinsic phase separation in superconducting K 0.8 Fe 1.6 Se 2 ( T c = 31.8 K) single crystals
journal, July 2011


A Novel Large Moment Antiferromagnetic Order in K 0.8 Fe 1.6 Se 2 Superconductor
journal, August 2011


Iron-vacancy superstructure and possible room-temperature antiferromagnetic order in superconducting Cs y Fe 2 x Se 2
journal, April 2011

  • Pomjakushin, V. Yu.; Sheptyakov, D. V.; Pomjakushina, E. V.
  • Physical Review B, Vol. 83, Issue 14
  • DOI: 10.1103/PhysRevB.83.144410

Phase relations in K x Fe 2 y Se 2 and the structure of superconducting K x Fe 2 Se 2 via high-resolution synchrotron diffraction
journal, November 2012


Structure and composition of the superconducting phase in alkali iron selenide K y Fe 1.6 + x Se 2
journal, April 2014


Phase separation and magnetic order in K-doped iron selenide superconductor
journal, November 2011

  • Li, Wei; Ding, Hao; Deng, Peng
  • Nature Physics, Vol. 8, Issue 2
  • DOI: 10.1038/nphys2155

KFe 2 Se 2 is the Parent Compound of K-Doped Iron Selenide Superconductors
journal, July 2012


Influence of microstructure on superconductivity in KxFe2−ySe2 and evidence for a new parent phase K2Fe7Se8
journal, May 2013

  • Ding, Xiaxin; Fang, Delong; Wang, Zhenyu
  • Nature Communications, Vol. 4, Issue 1
  • DOI: 10.1038/ncomms2913

Fe-vacancy order and superconductivity in tetragonal  -Fe1-xSe
journal, December 2013

  • Chen, T. -K.; Chang, C. -C.; Chang, H. -H.
  • Proceedings of the National Academy of Sciences, Vol. 111, Issue 1
  • DOI: 10.1073/pnas.1321160111

Structural Phase Separation in K 0.8 Fe 1.6+ x Se 2 Superconductors
journal, August 2012

  • Wang, Zhi-Wei; Wang, Zhen; Song, Yuan-Jun
  • The Journal of Physical Chemistry C, Vol. 116, Issue 33
  • DOI: 10.1021/jp306310m

High-resolution characterization of microstructural evolution in Rb x Fe 2 y Se 2 crystals on annealing
journal, July 2014


NMR Study in the Iron-Selenide Rb 0.74 Fe 1.6 Se 2 : Determination of the Superconducting Phase as Iron Vacancy-Free Rb 0.3 Fe 2 Se 2
journal, June 2012


Superconducting properties of single-crystalline A x Fe 2 y Se 2 ( A = Rb, K) studied using muon spin spectroscopy
journal, March 2012


Fe 57 Mössbauer study of magnetic ordering in superconducting K 0 . 80 Fe 1 . 76 Se 2 . 00 single crystals
journal, March 2011


Phase separation in superconducting and antiferromagnetic Rb 0.8 Fe 1.6 Se 2 probed by Mössbauer spectroscopy
journal, November 2011


Works referencing / citing this record:

Nanoscale electrodynamics of strongly correlated quantum materials
journal, November 2016


Imaging the local electronic and magnetic properties of intrinsically phase separated Rb x Fe 2– y Se 2 superconductor using scanning microscopy techniques
journal, February 2019

  • Dudin, P.; Herriott, D.; Davies, T.
  • Superconductor Science and Technology, Vol. 32, Issue 4
  • DOI: 10.1088/1361-6668/aaffa8