The theoretical investigation on structural, vibrational, electronic properties of zinc-blende(ZB) AgI were carried out employing first principles density functional theory calculations. Thermoelectric properties then were predicted through semi-classical Boltzmann transport equations within the constant relaxation time approximation. Equilibrium lattice parameter, bulk modulus, elastic constants and vibrational properties were calculated by using Generalized Gradient Approximation (GGA). Calculated properties are in good agreement with available experimental values. Electronic and thermoelectric properties were investigated both with and without considering spin-orbit coupling (SOC) effect which is found to have a strong influence on $p$-type Seebeck coefficient as well as the power factor of the ZB-AgI. By inclusion of SOC, a reduction of the band-gap and $p$-type Seebeck coefficients as well as the power factor was found which is the indication of that spin-orbit interaction cannot be ignored for $p$-type thermoelectric properties of the ZB-AgI. By using deformation potential theory for electronic relaxation time and experimentally predicted lattice thermal conductivity, we obtained a $ZT$ value 1.69 (0.89) at 400 K for $n$-type($p$-type) carrier concentration of 1.5$\times$10$^{18}$ (4.6$\times$10$^{19}$) cm$^{-3}$ that makes ZB-AgI as a promising room temperature thermoelectric material.

中文翻译：

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从第一性原理看闪锌矿AgI的有希望的室温热电转换效率

采用第一性原理密度泛函理论计算，对闪锌矿 (ZB) AgI 的结构、振动、电子特性进行了理论研究。然后通过恒定弛豫时间近似内的半经典玻尔兹曼传输方程预测热电特性。平衡晶格参数、体积模量、弹性常数和振动特性通过使用广义梯度近似（GGA）计算。计算的特性与可用的实验值非常吻合。在考虑和不考虑自旋轨道耦合 (SOC) 效应的情况下研究了电子和热电特性，发现该效应对 $p$ 型塞贝克系数以及 ZB-AgI 的功率因数有很大影响。通过包含 SOC，发现带隙和 $p$ 型塞贝克系数以及功率因数的减少，这表明对于 ZB-AgI 的 $p$ 型热电特性，不能忽略自旋轨道相互作用。通过使用电子弛豫时间的变形势理论和实验预测的晶格热导率，我们在 400 K 时获得了 $ZT$ 值 1.69 (0.89)，用于 $n$-type($p$-type) 载流子浓度为 1.5$\times $10$^{18}$ (4.6$\times$10$^{19}$) cm$^{-3}$ 这使得 ZB-AgI 成为一种很有前途的室温热电材料。