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Title: Giant spin gap and magnon localization in the disordered Heisenberg antiferromagnet Sr 2 Ir 1 - x Ru x O 4

Here, we study the evolution of magnetic excitations in the disordered two-dimensional antiferromagnet Sr 2Ir 1–xRuxO 4. The maximum energy of the magnetic excitation remains robust up to x = 0.77, with a gap opening at low dopings and increasing to over 150 meV at x = 0.77. At these higher Ru concentrations, the dispersive magnetic excitations in Sr 2IrO 4 are rendered essentially momentum independent. Up to a Ru concentration of x = 0.77, both experiments and first-principles calculations show the Ir J eff = 1/2 state remains intact. The magnetic gap arises from the local interaction anisotropy in the proximity of the Ru disorder. Under the coherent potential approximation, we reproduce the experimental magnetic excitations using the disordered Heisenberg antiferromagnetic model with suppressed next-nearest-neighbor ferromagnetic coupling.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3] ;  [3] ;  [3] ;  [3] ;  [4] ;  [4] ;  [5] ;  [5] ;  [1] ;  [1] ;  [5] ;  [1] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Argonne National Lab. (ANL), Lemont, IL (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Univ. of Colorado, Boulder, CO (United States)
Publication Date:
Report Number(s):
BNL-113585-2017-JA
Journal ID: ISSN 2469-9950; PRBMDO; R&D Project: PO011; PO010; KC0201060; TRN: US1700642
Grant/Contract Number:
SC0012704; AC02-06CH11357; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 12; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Materials Sciences and Engineering Division, Scientific User Facilities Division, Midwest Integrated Center for Computational Materials (MICCoM)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Resonant inelastic x-ray scattering
OSTI Identifier:
1389620
Alternate Identifier(s):
OSTI ID: 1345743; OSTI ID: 1345852; OSTI ID: 1399528