The structural stability and optoelectronic properties of the ternary Ba_1−xBe_xS alloys along with the pure binary compounds BaS and BeS in the rock-salt (B1) and zinc-blende (B3) phases were investigated by the density functional theory (DFT) within the full-potential linearized augmented plane wave (FP-LAPW) method implemented in the Wien2k package. The generalized gradient approximation of Wu and Cohen (WC-GGA) was used for the exchange-correlation potential (V_xc) to compute the equilibrium structural parameters, lattice constant (a), and bulk modulus (B). In addition to the GGA approach, the modified Becke-Johnson potential of Tran and Blaha (TB-mBJ) scheme coupled with the spin-orbit interaction was used to calculate the band gap energies. Results reveal that BaS, Ba_0.75Be_0.25S, and Ba_0.5Be_0.5S compounds are stable in the rock-salt phase, while Ba_0.25Be_0.75S and BeS are found to be stable in the zinc-blende phase. The computed results for the band structures and optical constants are compared with other available theoretical calculations and experimental measurements.

中文翻译：

---

Ba1-xBexS的相稳定性和光电特性：基于DFT的仿真。

通过密度泛函理论研究了三元Ba _{1- x} Be _x S合金以及纯二元化合物BaS和BeS在岩石盐（B1）和闪锌矿（B3）相中的结构稳定性和光电性能（ Wien2k软件包中实现的全电势线性化增强平面波（FP-LAPW）方法中的DFT）。Wu和Cohen的广义梯度逼近（WC-GGA）用于交换相关势（V _xc）以计算平衡结构参数，晶格常数（a）和体积模量（B）。除GGA方法外，还使用了经过改进的Tran和Blaha的Becke-Johnson势（TB-mBJ）方案以及自旋轨道相互作用来计算带隙能。结果表明，BaS，Ba _0.75 Be _0.25 S和Ba _0.5 Be _0.5 S化合物在岩盐相中稳定，而Ba _0.25 Be _0.75 S和BeS在闪锌矿相中稳定。将能带结构和光学常数的计算结果与其他可用的理论计算和实验测量结果进行比较。