The bulk photovoltaic effect generates intrinsic photocurrents in materials without inversion symmetry. Shift current is one of the bulk photovoltaic phenomena related to the Berry phase of the constituting electronic bands: photo-excited carriers coherently shift in real space due to the difference in the Berry connection between the valence and conduction bands. Ferroelectric semiconductors and Weyl semimetals are known to exhibit such nonlinear optical phenomena. Here we consider chalcopyrite semiconductor ZnSnP$_2$ which lacks inversion symmetry and calculate the shift current conductivity. We find that the magnitude of the shift current is comparable to the recently measured values on other ferroelectric semiconductors and an order of magnitude larger than bismuth ferrite. The peak response for both optical and shift current conductivity, which mainly comes from P-3$p$ and Sn-5$p$ orbitals, is several eV above the bandgap.
Improved electronic structure prediction of chalcopyrite semiconductors from a semilocal density functional based on Pauli kinetic energy enhancement factor
d电子的正确处理是至关重要的，以预测原型黄铜矿半导体的电子性质。d态的影响与阴离子位移参数u有关，这反过来又影响这些系统的带隙。半局域交换相关泛函产生良好的半导体和绝缘体的结构特性，往往无法预测合理的u，因为d电子之间的强相互作用所产生的带隙的低估。在本研究中，我们表明，从无尖氢密度（MGGAC）[Phys. Rev. B 100，155140（2019）]获得的亚广义梯度近似（meta-GGA）在理解黄铜矿电子性质的关键特征方面有所改进，其带隙与使用最先进的混合方法获得的带隙相当。此外，本评估还显示了泡利动能增强因子，$α=(τ-τ^W)/τ^{unif}$在描述黄铜矿中的d电子的重要性。本研究强烈表明，MGGAC功能内半局部近似可以是一个更好的和首选的选择，研究黄铜矿和其他固态系统，由于其优越的性能和显着低的计算成本。
Accurate and efficient prediction of the band gaps and optical spectra of chalcopyrite semiconductors from a non-empirical range-separated dielectric-dependent hybrid: Comparison with many-body perturbation theory
Thermoelectric Properties of Copper-based Chalcopyrite Semiconductors Cu$MX_2$ ($M$ = Al, Ga, and In; $X$ = S, Se, and Te) from First-Principles Calculations
Second harmonic generation and birefringence of some ternary pnictide semiconductors
用第一性原理研究了具有黄铜矿结构的三元磷属元素化物半导体ABC $_2$（A = Zn，Cd; B = Si，Ge; C = As，P）的双折射和频率相关的二次谐波产生系数.我们表明，一个简单的经验观察，一个较小的值的差距与较大的值的SHG是定性的真实。然而，在带隙和二次谐波之间并没有发现简单的幂次反比关系，相反，非线性响应的真实值是不同带内和带间项之间非常微妙的平衡的结果。
