Effect of intense laser irradiation on the lattice stability of InSb

¹ Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P.R. China
² School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, Guangdong 510640, P.R. China

^a e-mail: gaotao@scu.edu.cn

Received: 28 September 2011
Accepted: 26 October 2011
Published online: 2 December 2011

Abstract

We have performed an ab initio study of electronic and dynamical properties of the zinc-blende InSb at different electronic temperatures. The calculations have been carried out within the density-functional theory and linear-response formalism using norm-conserving pseudopotentials and a plane-wave basis. The calculated direct band gap is seen to be 0.1 eV, which is underestimated with the experimental value of 0.18 eV. As the electronic temperature increases, the results indicate that the InSb undergoes a melting transition to a metallic state. The transverse acoustic modes of the InSb are found to be negative in the most part of the Brillouin zone (BZ) which leads to lattice dynamical unstability at electronic temperature of 0.75 eV as indicated by imaginary phonon frequencies. Moreover, for optical modes, there exists a LO-TO splitting at the zone-center (Γ point) when T_e = 0 eV and the frequencies are LO = 190.5 cm⁻¹, TO = 182.4 cm⁻¹, respectively; however, the LO-TO splitting will disappear when T_e > 0 eV. The calculated values are in reasonable agreement with available experimental and theoretical data.