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Title: Novel silicon allotropes: Stability, mechanical, and electronic properties

One quasi-direct gap phase (Amm2) and three indirect gap phases (C2/m-16, C2/m-20, and I-4) of silicon allotropes are proposed. The detailed theoretical study on the structure, density of states, elastic properties, sound velocities, and Debye temperature of these four phases is carried out by using first principles calculations. The elastic constants of these four phases are calculated by strain-stress method. The elastic constants and the phonon calculations manifest all novel silicon allotropes in this paper are mechanically and dynamically stable at ambient condition. The B/G values indicate that these four phases of silicon are brittle materials at ambient pressure. The anisotropy properties show that C2/m-20 phase exhibits a larger anisotropy in its elastic modulus, shear elastic anisotropic factors, and several anisotropic indices than others. We have found that the Debye temperature of the four novel silicon allotropes gradually reduces in the order of C2/m-20 > Amm2 > C2/m-16 > I-4 at ambient pressure.
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071 (China)
  2. School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China)
  3. College of Chemistry and Chemical Engineering, Baoji University of Arts and Sciences, Baoji 721013 (China)
  4. Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650051 (China)
Publication Date:
OSTI Identifier:
22492931
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; DEBYE TEMPERATURE; DENSITY OF STATES; ELASTICITY; INDEXES; MATERIALS; MONOCLINIC LATTICES; ORTHORHOMBIC LATTICES; PHONONS; SHEAR; SILICON; SOUND WAVES; STABILITY; STRAINS; STRESSES; VELOCITY