An extended Hückel study of the electronic properties of III–V compounds and their alloys

Abstract

In this work, we performed tight binding calculations of the electronic structure of III-V semiconductors compounds and their alloys based on the Extended Hückel Theory (EHT), where the Hückel parameters for the binary compounds were generated following a simulated annealing procedure. In particular, this article is focused on the dependency between band gap and the applied pressure and also the alloy composition.

Orthogonal and Non-Orthogonal Tight Binding Parameters for III–V Semiconductors Nitrides

“…As in any TB formalism, the EHT alloy states are spanned as linear combinations of atomic orbitals, considering that the basis orbitals form a non-orthogonal basis set. The aforementioned method presents a good transferability of its parameters [5] and it also gives a good description of the deformation potential for III-V alloys under uniform strain [6]. In addition, EHT is capable of reproducing the density of states (DOS) of graphene, silicene and germanene supercells with a single vacancy, in a remarkble agreement with Density Functional Theory (DFT) calculations [7].…”

“…An acceptable set is generated when y ≤ 0.15 eV. This approach was successful for generating acceptable and highly transferable TB sets for few III-V semiconductors compounds (AlAs, GaAs, InAs and GaP) [6], as well and group-IV planar structures such as graphene, silicene and germanene [7].…”

“…The systematic adopted in SA procedure was first optimize the AlN, and for GaN and InN, the values of ζ and c 1 of N were set to the calculated values for AlN, emphasizing only orbital energies for this specie are varied. As the parameters for GaN were already calculated in [6], in this paper the parameters were recalculated. In Table 4, the onsite energies are given for both zincblend and wurtzite structures.…”

“…As published in [6], all TB parameters were calculated using a simulated annealing (SA) approach within the proposal of Vanderbilt and Louie [11]. In a few words, for a given initial set of Hückel parameters, their values are varied in successive Monte Carlo cycles with decreasing temperatures in order to reduce the value of the objective function y, namely the root mean square (RMS) deviation of the Hückel bands E H i (k) in relation to a target band structure E T i (k):…”

“…One alternative to OTB is to approach the problem within the semi-empirical Extended Hückel Theory (EHT) [5,6]. As in any TB formalism, the EHT alloy states are spanned as linear combinations of atomic orbitals, considering that the basis orbitals form a non-orthogonal basis set.…”