Plane-wave pseudopotential study on mechanical and electronic properties for group III-V binary phases
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Plane-wave pseudopotential study on mechanical and electronic properties for group III-V binary phases S. Q. Wang and H. Q. Ye Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, P. R. China ABSTRACT The result of first-principles density functional calculations of the bulk modulus and related structural and electronic properties of the total 25 group III-V binary phases with zinc-blende and wurtzite structures are presented. The behavior of energy band structure variation under high pressures is also studied. It is found that the bulk modulus is more sensitive to the local atom configuration than the lattice structure. The crystallographic geometry plays an important role in the electronic property of these phases. INTRODUCTION The combination of III and V elements is characterized by typical covalent bonds. Zincblende (ZB) and wurtzite (WZ) are the commonest structures of III-V binary phases. The particular omni-triangulated nature in atomic structure makes these crystals unique mechanical and electronic properties. Most of the III-V solids are semiconductors. Among them GaN, InN and GaAs, due to their excellent electronic and optical properties, have found important application in microelectronic and information industries. However, due to the difficulty in experimental fabrication, only a small portion of these compounds has been fully studied in laboratory. In this work, we perform a thoroughly computational study within the scheme of densityfunctional theory (DFT) for the total 25 III-V binary compounds in both of their ZB and WZ polytypes. The lattice parameter, bulk modulus, energy band structures and their electronic behaviors under pressure are calculated and analyzed in detail. COMPUTATIONAL DETAILS The DFT calculation has become a most important method in theoretical research of solids, nowadays. The generality and efficiency of plane-wave pseudopotential (PW-PP) method makes it as one of the most powerful ab initio quantum-mechanical modeling methods presently available [1,2]. Our PW-PP calculations are accomplished using the ABINIT computer code [2]. The LDA pseudopotentials used in present study are the Hartwigsen-Goedecker-Hutter (HGH) relativistic separable dual-space Gaussian pseudipotentials [3]. The details for the general routines of our DFT ground state calculation and energy band structure analyses are described elsewhere [4,5].
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RESULTS Lattice parameter and bulk modulus Bulk modulus is an important parameter for mechanical property of solids. It is directly related to the hardness of materials. One knows from Murnaghan equation [6] that the constant-
Table I. Equilibrium lattice constants, bulk modulus B0 and B0’ of III-V ZB phases. Phase AlN AlP AlAs AlSb AlBi GaN GaP GaAs GaSb GaBi InN InP InAs InSb InBi BN BP BAs BSb BBi TlN TlP TlAs TlSb TlBi
a0 (nm) Calc. Exp. 0.4323 0.437 0.5417 0.5467 0.5614 0.566 0.6090 0.6136 0.6266 0.4335 0.450 0.5322 0.5451 0.5530 0.5649 0.5981 0.6081
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