Abstract

We predicted that half-Heusler alloy PtMnBi to be potential candidate for using in spintronic and optoelectronic devices. Using first principle calculations based on density functional theory (DFT) within generalized gradient approximation (GGA), we studied the structural, electronic, magnetic and optical properties of PtMnBi half-Heusler alloy in bulk state and surfaces (001) and for MnBi, PtMn and PtBi terminations. We showed for MnBi termination that if its equilibrium lattice constants an and b are decreased simultaneously by 10%, it becomes a half-metal with a semiconducting gap of 0.2 eV. Also, the magnetic moment of the Mn atom of \(4.1\,\,\mu {\kern 1pt} \_{\kern 1pt} {\text{B}}\) on the surface layer of this termination, shows a s light difference compared to the bulk state. The real part of the dielectric function for the incident light in both the xx and zz directions for energies greater than 7.5 eV for all three terminations is the same, and for energies greater than 15 eV they converge to one, indicating that they act as an isotropic insulator and also the refractive index for energies greater than 7.5 eV is less than one, indicating super-luminance phenomenon.

中文翻译：

---

表面效应对 PtMnBi Half-Heusler 的电子、磁性和光学特性的影响：DFT 研究

摘要

我们预测，半赫斯勒合金 PtMnBi 将成为用于自旋电子和光电器件的潜在候选者。使用基于广义梯度近似 (GGA) 中的密度泛函理论 (DFT) 的第一性原理计算，我们研究了 PtMnBi 半赫斯勒合金在体态和表面 (001) 以及 MnBi、PtMn 的结构、电子、磁和光学性质和 PtBi 终端。我们表明，对于 MnBi 终止，如果其平衡晶格常数 an 和b同时降低 10%，它就会变成半导体间隙为 0.2 eV 的半金属。此外，该终端的表层 \(4.1\,\,\mu {\kern 1pt} \_{\kern 1pt} {\text{B}}\)的 Mn 原子的磁矩显示为s与散装状态相比的光差异。对于所有三个终端的能量大于 7.5 eV，入射光在xx和zz方向的介电函数的实部是相同的，对于大于 15 eV 的能量，它们会收敛到 1，表明它们充当各向同性绝缘体，并且对于大于 7.5 eV 的能量的折射率小于 1，表明超亮度现象。