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Title: Highly responsive ground state of PbTaSe 2 : Structural phase transition and evolution of superconductivity under pressure

Transport and magnetic studies of PbTaSe 2 under pressure suggest the existence of two superconducting phases with the low temperature phase boundary at ~ 0.25 GPa that is defined by a very sharp, first order, phase transition. The first order phase transition line can be followed via pressure dependent resistivity measurements, and is found to be near 0.12 GPa near room temperature. Transmission electron microscopy and x-ray diffraction at elevated temperatures confirm that this first order phase transition is structural and occurs at ambient pressure near ~ 425 K. The new, high temperature/high pressure phase has a similar crystal structure and slightly lower unit cell volume relative to the ambient pressure, room temperature structure. Based on first-principles calculations this structure is suggested to be obtained by shifting the Pb atoms from the 1 a to 1 e Wyckoff position without changing the positions of Ta and Se atoms. PbTaSe 2 has an exceptionally pressure sensitive, structural phase transition with Δ T s / Δ P ≈ -1400 K/GPa near room temperature, and ≈ -1700 K/GPa near 4 K. This first order transition causes a ~ 1 K (~ 25 % ) steplike decrease in T c as pressure is increasedmore » through 0.25 GPa.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [4] ;  [4] ;  [2] ;  [3] ;  [4] ;  [3] ;  [1] ;  [1] ;  [1]
  1. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  2. Washington Univ., St. Louis, MO (United States)
  3. Ames Lab., Ames, IA (United States)
  4. Peking Univ., Beijing (China)
Publication Date:
Report Number(s):
IS-J 9347
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1702748
Grant/Contract Number:
AC02-07CH11358; DMR-1104742; DMR-1505345
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 22; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1368052
Alternate Identifier(s):
OSTI ID: 1372522