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Title: Pressure-induced changes in the electron density distribution in α-Ge near the α-β transition

Electron density distributions in α-Ge have been determined under high pressure using maximum entropy method with structure factors obtained from single crystal synchrotron x-ray diffraction in a diamond anvil cell. The results show that the sp{sup 3} bonding is enhanced with increasing pressure up to 7.7(1) GPa. At higher pressures but below the α-β transition pressure of 11.0(1) GPa, the sp{sup 3}-like electron distribution progressively weakens with a concomitant increase of d-orbitals hybridization. The participation of d-orbitals in the electronic structure is supported by Ge Kβ{sub 2} (4p-1s) x-ray emission spectroscopy measurements showing the reduction of 4s character in the valence band at pressures far below the α-β transition. The gradual increase of d-orbitals in the valence level in the stability field of α-Ge is directly related to the eventual structural transition.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ; ;  [4] ;  [5]
  1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
  2. (United States)
  3. (China)
  4. HPCAT Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States)
  5. Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada)
Publication Date:
OSTI Identifier:
22489115
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DIAMONDS; ELECTRON DENSITY; ELECTRONIC STRUCTURE; EMISSION SPECTROSCOPY; ENTROPY; MONOCRYSTALS; PRESSURE RANGE GIGA PA; STRUCTURE FACTORS; VALENCE; X RADIATION; X-RAY DIFFRACTION