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Title: Evolution of Magnetic Double Helix and Quantum Criticality near a Dome of Superconductivity in CrAs

At ambient pressure, CrAs undergoes a first-order transition into a double-helical magnetic state at T N=265 K, which is accompanied by a structural transition. The recent discovery of pressure-induced superconductivity in CrAs makes it important to clarify the nature of quantum phase transitions out of the coupled structural/helimagnetic order in this system. Here, we show, via neutron diffraction on the single-crystal CrAs under hydrostatic pressure (P), that the combined order is suppressed at P c≈10 kbar, near which bulk superconductivity develops with a maximal transition temperature T c≈2 K. We further show that the coupled order is also completely suppressed by phosphorus doping in CrAs 1-xP x at a critical x c ≈ 0.05, above which inelastic neutron scattering evidenced persistent antiferromagnetic correlations, providing a possible link between magnetism and superconductivity. In line with the presence of antiferromagnetic fluctuations near P c(x c), the A coefficient of the quadratic temperature dependence of resistivity exhibits a dramatic enhancement as P (x) approaches P c(x c), around which ρ(T) has a non-Fermi-liquid form. Accordingly, the electronic specific-heat coefficient of CrAs 1-xP x peaks around x c. These properties provide clear evidence for quantum criticality, which we interpret as originating from a nearlymore » second-order helimagnetic quantum phase transition that is concomitant with a first-order structural transition. Lastly, our findings in CrAs highlight the distinct characteristics of quantum criticality in bad metals, thereby bringing out new insights into the physics of unconventional superconductivity such as those occurring in the high-T c iron pnictides.« less
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [4] ;  [4] ;  [5] ;  [6] ;  [5] ; ORCiD logo [7] ; ORCiD logo [1] ;  [8] ;  [9] ;  [5]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
  2. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics
  3. Renmin Univ. of China, Beijing (China). Physics Dept. and Beijing Key Lab. of Opto-electronic Functional Materials and Micro-nano Devices
  4. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics; Chinese Academy of Sciences (CAS), Beijing (China). School of Physical Sciences
  5. Univ. of Tokyo (Japan). Inst. for Solid State Physics
  6. Nanosystem Research Inst., Tsukuba (Japan)
  7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  8. Rice Univ., Houston, TX (United States). Dept. of Physics and Astronomy and Rice Center for Quantum Materials
  9. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics; Chinese Academy of Sciences (CAS), Beijing (China). School of Physical Sciences; Collaborative Innovation Center of Quantum Matter, Beijing (China)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; SC0018197; 2018YFA0305700; 2014CB921500; 2015CB921303; 2017YFA0302901; 2016YFA0300504
Type:
Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1461040
Alternate Identifier(s):
OSTI ID: 1462869