Evarestov Robert A, Kuzmin Alexei
Department of Quantum Chemistry, Saint Petersburg State University, St. Petersburg, Russian Federation.
Institute of Solid State Physics, University of Latvia, Riga, Latvia.
J Comput Chem. 2020 Dec 5;41(31):2610-2623. doi: 10.1002/jcc.26416. Epub 2020 Sep 9.
Two pressure-induced phase transitions have been theoretically studied in the layered iron phosphorus triselenide (FePSe ). Topological analysis of chemical bonding in FePSe has been performed based on the results of first-principles calculations within the periodic linear combination of atomic orbitals (LCAO) method with hybrid Hartree-Fock-DFT B3LYP functional. The first transition at about 6 GPa is accompanied by the symmetry change from to C2/m, whereas the semiconductor-to-metal transition (SMT) occurs at about 13 GPa leading to the symmetry change from C2/m to . We found that the collapse of the band gap at about 13 GPa occurs due to changes in the electronic structure of FePSe induced by relative displacements of phosphorus or selenium atoms along the c-axis direction under pressure. The results of the topological analysis of the electron density and its Laplacian demonstrate that the pressure changes not only the interatomic distances but also the bond nature between the intralayer and interlayer phosphorus atoms. The interlayer P-P interactions are absent in two non-metallic FePSe phases while after SMT the intralayer P-P interactions weaken and the interlayer P-P interactions appear.
在层状三硒化铁磷（FePSe₃）中，理论上研究了两种压力诱导的相变。基于采用混合Hartree-Fock-DFT B3LYP泛函的周期线性组合原子轨道（LCAO）方法的第一性原理计算结果，对FePSe₃中的化学键进行了拓扑分析。约6 GPa时的第一次转变伴随着对称性从[原文此处缺失初始对称性信息]变为C2/m，而半导体到金属的转变（SMT）发生在约13 GPa，导致对称性从C2/m变为[原文此处缺失最终对称性信息]。我们发现，约13 GPa时带隙的消失是由于压力下磷或硒原子沿c轴方向的相对位移引起的FePSe₃电子结构变化所致。电子密度及其拉普拉斯算子的拓扑分析结果表明，压力不仅改变了原子间距离，还改变了层内和层间磷原子之间的键性质。在两个非金属FePSe₃相中不存在层间P-P相互作用，而在SMT之后，层内P-P相互作用减弱，层间P-P相互作用出现。
