Ga1-ＸTiＸSb(Ｘ= 0.25, 0.50, 0.75)电学、磁学及光学性质的第一性原理研究

First principles study of the electrical, magnetic and optical properties of Ga1-XTiXSb (X= 0.25, 0.50, 0.75)

摘要:

直接带隙半导体锑化镓（GaSb）凭借其优异的性能在光纤通信、光电器件等领域具有应用价值。为了探索GaSb在光电器件中及新的自旋电子学材料的潜在应用，采用第一性原理计算了不同Ti掺杂浓度的GaSb（Ga1-xTixSb，其中X为Ti原子的掺杂浓度百分比）的电学、磁学及光学性质。计算结果表明：Ga1-xTixSb的能带结构和态密度在费米能级附近产生自旋劈裂并形成净磁矩，使Ga1-xTixSb(X=0.25, 0.50, 0.75)分别表现为半金属铁磁体、稀磁半导体、磁性金属。Ga1-xTixSb优化后晶格常数变大；Ga1-xTixSb的折射率、反射率、吸收系数发生红移且在中远红外波段光吸收系数高于GaSb；Ga1-xTixSb随着Ti掺杂浓度的增加对中远红外波段光子的吸收效果变得更好。计算结果为拓展GaSb基半导体材料在红外探测器、红外半导体激光器等领域的应用以及新的自旋电子学材料的发现提供理论参考。

Abstract:

Direct band gap semiconductor gallium antimonide (GaSb) has applications in fiber optic communication and optoelectronic devices because of its excellent performance. In order to explore the potential applications of GaSb in optoelectronic devices and new spintronics materials, the electrical, magnetic and optical properties of GaSb at different Ti doping concentrations (denoted as Ga1-xTixSb, where X is the atomic percentage concentration of Ti) were calculated by first-principles. The calculated results show that the energy band structure and the density of states of Ga1-xTixSb generate spin splitting near the Fermi level and form a net magnetic moment, making the Ga1-xTixSb (x=0.25, 0.5, 0.75) show half-metal ferromagnet, dilute magnetic semiconductor and magnetic metallic, respectively. The lattice constant of Ga1-xTixSb increases after optimization. The refractive index, reflectivity and absorption coefficient of Ga1-xTixSb are red-shifted and have a higher optical absorption coefficient than that of undoped GaSb in the middle and far infrared band. The absorption of Ga1-xTixSb become better in the middle and far infrared band as the Ti doping concentration increases. The calculation results provide a theoretical reference for the expansion of GaSb-based semiconductor materials for applications in infrared detectors, infrared semiconductor lasers and the discovery of new materials for spintronics.