Theoretical study of the structure and magnetism of Ga 1 − x V x Sb compounds for spintronic applications

• Published in: Applied physics letters 2020-02, Vol.116 (8)
• Main Authors: Wan, Wenhui, Zhao, Shan, Wang, Chuang, Ge, Yanfeng, Liu, Yong
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5140817

In this paper, the structural, electronic, and magnetic properties of Ga 1 − x V x Sb compounds with various vanadium (V) contents (x) ranging from dilute doping to the extreme doping limit were systematically investigated by first-principles calculations. The results show that V atoms prefer to substitute for gallium (Ga) atoms, and the formation energy is lower under Sb-rich growth conditions than under Ga-rich growth conditions. Meanwhile, the Sb Ga antisite defects effectively decrease the energy barrier of the substitution process from 0.85 to 0.53 eV. The diffusion of V atoms in the GaSb lattice occurs through metastable interstitial sites with an energy barrier of 0.6 eV. At a low V concentration (x = 0.0625), V atoms prefer a homogeneous distribution with antiferromagnetic coupling among the V atoms. However, when x increases above 0.5, the magnetic coupling among V atoms changes to ferromagnetic coupling due to the enhanced superexchange interaction between the eg and t 2 g states of neighboring V atoms. At the extreme doping limit of x = 1.00, zinc blende VSb along with its analogs VAs and VP is an intrinsic ferromagnetic semiconductor that exhibits a large change in light absorption at the Curie temperature. The results indicate that Ga 1 − x V x Sb compounds provide a platform to design next-generation electronic, spintronic, and optoelectronic devices.