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Title: Anomalous breakdown of Bloch's rule in the Mott-Hubbard insulator MnTe2

Here, we reinvestigate the pressure dependence of the crystal structure and antiferromagnetic phase transition in MnTe2 using the rigorous and reliable tool of high-pressure neutron powder diffraction. First-principles density functional theory calculations are carried out in order to gain microscopic insight. The measured N eel temperature of MnTe2 is found to show unusually large pressure dependence of 12 K GPa–1. This gives rise to a large violation of Bloch s rule given by α = d log TN/d log V = –10/3 ≈ –3.3, to an value of –6.0 ± 0.1 for MnTe2. The ab initio calculation of the electronic structure and the magnetic exchange interactions in MnTe2 for the measured crystal structures at different pressures indicates the pressure dependence of the Neel temperature α is –5.61, in close agreement with experimental findings. The microscopic origin of this behavior turns out to be dictated by the distance dependence of the cation-anion hopping interaction strength.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [4] ;  [5] ;  [5]
  1. Institut Laue-Langevin, Grenoble Cedex (France)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. Pierre et Marie Curie, Paris (France)
  4. Rutherford Appleton Lab., Didcot (United Kingdom)
  5. S.N. Bose National Centre for Basic Sciences, Kolkata (India)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 10; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MnTe2; Mott-Hubbard Insulator; high pressure; neutron diffraction
OSTI Identifier:
1265660
Alternate Identifier(s):
OSTI ID: 1181536