Atomistic simulation of GaAs heterostructures

We use the non-equilibrium Green's function density functional theory to investigate GaAs-TaAs and GaAs-Cd3As2 heterojunctions. First, we study three types of GaAs-AlGaAs2 heterojunctions. For GaAs(100)-AlGaAs2(001), the equilibrium potential energy oscillates strongly in left and right leads (AlGaAs2). For GaAs(110)-AlGaAs2(110), the potential energy oscillates strongly in the center region (GaAs). For both of them, the average potential energy is lower in the center region. For GaAs(110)-AlGaAs2(101), the potential energy oscillates in the whole region. Then, we study two heterojunctions GaAs(110)-TaAs(100) and GaAs(100)-TaAs(100), and find the average potential energy is higher in the center region (GaAs). For Cd3As2, we study three types of unit cell with 10, 40 and 160 atoms respectively. We verify for the 160 atoms, the inversion symmetry of the fermi surface is broken. With the external voltage applied, we find a threshold of 0.6 eV in the IV cure of GaAs(110)-AlGaAs2(110). The software we use is DS-PAW (Device studio-projector augmented wave) and Nanodcal developed by Hongzhiwei Technology (Shanghai) Co. Ltd. The Perdew-Burke-Ernzerhof (PBE) exchange-correlation energy functional within the generalized gradient approximation (GGA) were employed.