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Title: Pressure dependence of coherence-incoherence crossover behavior in KFe 2 As 2 observed by resistivity and As 75 -NMR/NQR

Abstract

We present the results of 75As nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and resistivity measurements in KF e2 As 2 under pressure (p). The temperature dependence of the NMR shift, nuclear spin-lattice relaxation time (T 1), and resistivity show a crossover between a high-temperature incoherent, local-moment behavior and a low-temperature coherent behavior at a crossover temperature (T*). T* is found to increase monotonically with pressure, consistent with increasing hybridization between localized 3d orbital-derived bands with the itinerant electron bands. No anomaly in T* is seen at the critical pressure p c= 1.8 GPa where a change of slope of the superconducting (SC) transition temperature T c( p ) has been observed. In contrast, T c( p ) seems to correlate with antiferromagnetic spin fluctuations in the normal state as measured by the NQR 1/T 1 data, although such a correlation cannot be seen in the replacement effects of A in the AFe 2As 2 (A=K,Rb,Cs) family. In the superconducting state, two T 1 components are observed at low temperatures, suggesting the existence of two distinct local electronic environments. The temperature dependence of the short T 1s indicates a nearly gapless state below T c. On the other hand,more » the temperature dependence of the long component 1/T 1Limplies a large reduction in the density of states at the Fermi level due to the SC gap formation. These results suggest a real-space modulation of the local SC gap structure in KFe 2As 2 under pressure.« less

Authors:
 [1];  [2];  [3];  [4];  [1];  [1];  [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Univ. of California, Davis, CA (United States). Dept. of Physics
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE
OSTI Identifier:
1422762
Alternate Identifier(s):
OSTI ID: 1420353
Report Number(s):
IS-J 9572
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1801655
Grant/Contract Number:  
AC02-07CH11358; AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; 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; Research Areas; Pressure effects; Superconductivity; Physical Systems; Strongly correlated systems; Unconventional superconductors; Techniques; Nuclear magnetic resonance; Condensed Matter and Materials Physics

Citation Formats

Wiecki, P., Taufour, V., Chung, D. Y., Kanatzidis, M. G., Bud'ko, S. L., Canfield, P. C., and Furukawa, Y.. Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and As75 -NMR/NQR. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.97.064509.
Wiecki, P., Taufour, V., Chung, D. Y., Kanatzidis, M. G., Bud'ko, S. L., Canfield, P. C., & Furukawa, Y.. Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and As75 -NMR/NQR. United States. doi:10.1103/PhysRevB.97.064509.
Wiecki, P., Taufour, V., Chung, D. Y., Kanatzidis, M. G., Bud'ko, S. L., Canfield, P. C., and Furukawa, Y.. Tue . "Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and As75 -NMR/NQR". United States. doi:10.1103/PhysRevB.97.064509. https://www.osti.gov/servlets/purl/1422762.
@article{osti_1422762,
title = {Pressure dependence of coherence-incoherence crossover behavior in KFe2As2 observed by resistivity and As75 -NMR/NQR},
author = {Wiecki, P. and Taufour, V. and Chung, D. Y. and Kanatzidis, M. G. and Bud'ko, S. L. and Canfield, P. C. and Furukawa, Y.},
abstractNote = {We present the results of 75As nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and resistivity measurements in KFe2 As2 under pressure (p). The temperature dependence of the NMR shift, nuclear spin-lattice relaxation time (T1), and resistivity show a crossover between a high-temperature incoherent, local-moment behavior and a low-temperature coherent behavior at a crossover temperature (T*). T* is found to increase monotonically with pressure, consistent with increasing hybridization between localized 3d orbital-derived bands with the itinerant electron bands. No anomaly in T* is seen at the critical pressure pc= 1.8 GPa where a change of slope of the superconducting (SC) transition temperature Tc( p ) has been observed. In contrast, Tc( p ) seems to correlate with antiferromagnetic spin fluctuations in the normal state as measured by the NQR 1/T1 data, although such a correlation cannot be seen in the replacement effects of A in the AFe2As2 (A=K,Rb,Cs) family. In the superconducting state, two T1 components are observed at low temperatures, suggesting the existence of two distinct local electronic environments. The temperature dependence of the short T1s indicates a nearly gapless state below Tc. On the other hand, the temperature dependence of the long component 1/T1Limplies a large reduction in the density of states at the Fermi level due to the SC gap formation. These results suggest a real-space modulation of the local SC gap structure in KFe2As2 under pressure.},
doi = {10.1103/PhysRevB.97.064509},
journal = {Physical Review B},
number = 6,
volume = 97,
place = {United States},
year = {Tue Feb 13 00:00:00 EST 2018},
month = {Tue Feb 13 00:00:00 EST 2018}
}

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