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Title: The strain induced band gap modulation from narrow gap semiconductor to half-metal on Ti{sub 2}CrGe: A first principles study

The Heusler alloy Ti{sub 2}CrGe is a stable L2{sub 1} phase with antiferromagnetic ordering. With band-gap energy (∼ 0.18 eV) obtained from a first-principles calculation, it belongs to the group of narrow band gap semiconductor. The band-gap energy decreases with increasing lattice compression and disappears until a strain of −5%; moreover, gap contraction only occurs in the spin-down states, leading to half-metallic character at the −5% strain. The Ti{sub 1}, Ti{sub 2}, and Cr moments all exhibit linear changes in behavior within strains of −5%– +5%. Nevertheless, the total zero moment is robust for these strains. The imaginary part of the dielectric function for both up and down spin states shows a clear onset energy, indicating a corresponding electronic gap for the two spin channels.
Authors:
 [1] ;  [2] ;  [1] ; ; ; ; ; ;  [3]
  1. School of Science, Hebei University of Technology, Tianjin 300401 (China)
  2. (China)
  3. Research Institute for Energy Equipment Materials, Hebei University of Technology, Tianjin 300401 (China)
Publication Date:
OSTI Identifier:
22492203
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 11; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIFERROMAGNETISM; CHROMIUM; CHROMIUM ALLOYS; COMPRESSION; DIELECTRIC MATERIALS; ENERGY GAP; GERMANIUM ALLOYS; HEUSLER ALLOYS; MODULATION; PERMITTIVITY; SEMICONDUCTOR MATERIALS; SPIN; STRAINS; TITANIUM; TITANIUM BASE ALLOYS