State Key Laboratory of Crystal Materials, Shandong University, Jinan, People's Republic of China.
J Phys Condens Matter. 2011 Jun 8;23(22):225401. doi: 10.1088/0953-8984/23/22/225401. Epub 2011 May 16.
Li(2)CdGeS(4) and Li(2)CdSnS(4) are novel quaternary diamond-like semiconductors (DLSs) which have been synthesized recently. We present first-principles calculations of their electronic, optical and lattice dynamic properties with the plane-wave pseudopotential method. We have found an indirect band gap of 2.78 eV for Li(2)CdGeS(4) and a direct band gap of 2.50 eV for Li(2)CdSnS(4). The serious stretching vibrations of the Ge/Sn-S and Li-S bonds may enhance their phonon energies, and cause them to exhibit high heat capacities and Debye temperatures, which are promising for nonlinear optical applications. Compared with Cu-based DLSs, Li plays a key role in enlarging the band gaps and increasing the lattice phonon energies, which would increase the thermal conductivity accompanied by an increase of the optical damage threshold.
Li(2)CdGeS(4) 和 Li(2)CdSnS(4) 是最近合成的新型类似金刚石的四元半导体 (DLS)。我们使用平面波赝势方法对它们的电子、光学和晶格动力学性质进行了第一性原理计算。我们发现 Li(2)CdGeS(4) 的间接带隙为 2.78 eV，Li(2)CdSnS(4) 的直接带隙为 2.50 eV。Ge/Sn-S 和 Li-S 键的严重伸缩振动可能会增加它们的声子能量，导致它们具有高热容量和德拜温度，这对非线性光学应用很有前景。与基于 Cu 的 DLS 相比，Li 在扩大带隙和增加晶格声子能量方面起着关键作用，这将增加热导率，同时增加光学损伤阈值。
