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Title: Honeycomb lattice Na 2 IrO 3 at high pressures: A robust spin-orbit Mott insulator

Abstract

The honeycomb iridate Na 2IrO 3 has received much attention as a candidate to realize a quantum spin liquid state, but the nature of its insulating state remains controversial. We found that the material exhibits structural transitions at 3 and 10 GPa. The former is accompanied by 166-meV suppression of the activation gap, but the energies for the low-lying interband transitions change by less than 10 meV. This can be reconciled in a picture in which the application of high pressure barely shifts the electronic bands, but rather merely broadens them. First-principles calculations uncover a strong correlation between the band gap and the β angle of the monoclinic structure, indicating non-negligible interlayer coupling. Furthermore, these results offer clear evidence for a spin-orbit Mott insulating state in Na 2IrO 3 and are inconsistent with the quasimolecular orbital model.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [4];  [7];  [2];  [8]
  1. Nanjing Univ., Nanjing (China); Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Nanjing Univ., Nanjing (China)
  3. Univ. of Nebraska, Lincoln, NE (United States)
  4. Chinese Academy of Sciences (CAS), Beijing (China)
  5. The George Washington Univ., Washington, DC (United States)
  6. Stony Brook Univ., Stony Brook, NY (United States); Center for High Pressure Science and Technology Advanced Research, Beijing (China)
  7. Univ. of Colorado at Boulder, Boulder, CO (United States)
  8. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1483240
Alternate Identifier(s):
OSTI ID: 1469262
Report Number(s):
BNL-209471-2018-JAAM
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
SC0012704; AC02-98CH10886; FC03-03N00144
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 12; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Xi, Xiaoxiang, Bo, Xiangyan, Xu, X. S., Kong, P. P., Liu, Z., Hong, X. G., Jin, C. Q., Cao, G., Wan, Xiangang, and Carr, G. L. Honeycomb lattice Na2IrO3 at high pressures: A robust spin-orbit Mott insulator. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.98.125117.
Xi, Xiaoxiang, Bo, Xiangyan, Xu, X. S., Kong, P. P., Liu, Z., Hong, X. G., Jin, C. Q., Cao, G., Wan, Xiangang, & Carr, G. L. Honeycomb lattice Na2IrO3 at high pressures: A robust spin-orbit Mott insulator. United States. doi:10.1103/PhysRevB.98.125117.
Xi, Xiaoxiang, Bo, Xiangyan, Xu, X. S., Kong, P. P., Liu, Z., Hong, X. G., Jin, C. Q., Cao, G., Wan, Xiangang, and Carr, G. L. Mon . "Honeycomb lattice Na2IrO3 at high pressures: A robust spin-orbit Mott insulator". United States. doi:10.1103/PhysRevB.98.125117. https://www.osti.gov/servlets/purl/1483240.
@article{osti_1483240,
title = {Honeycomb lattice Na2IrO3 at high pressures: A robust spin-orbit Mott insulator},
author = {Xi, Xiaoxiang and Bo, Xiangyan and Xu, X. S. and Kong, P. P. and Liu, Z. and Hong, X. G. and Jin, C. Q. and Cao, G. and Wan, Xiangang and Carr, G. L.},
abstractNote = {The honeycomb iridate Na2IrO3 has received much attention as a candidate to realize a quantum spin liquid state, but the nature of its insulating state remains controversial. We found that the material exhibits structural transitions at 3 and 10 GPa. The former is accompanied by 166-meV suppression of the activation gap, but the energies for the low-lying interband transitions change by less than 10 meV. This can be reconciled in a picture in which the application of high pressure barely shifts the electronic bands, but rather merely broadens them. First-principles calculations uncover a strong correlation between the band gap and the β angle of the monoclinic structure, indicating non-negligible interlayer coupling. Furthermore, these results offer clear evidence for a spin-orbit Mott insulating state in Na2IrO3 and are inconsistent with the quasimolecular orbital model.},
doi = {10.1103/PhysRevB.98.125117},
journal = {Physical Review B},
number = 12,
volume = 98,
place = {United States},
year = {2018},
month = {9}
}

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