Xie Xing, Wen Minru, Dong Huafeng, Long Hui, Zhang Xin, Wu Fugen, Mu Zhongfei
School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China.
School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
Phys Chem Chem Phys. 2022 Sep 21;24(36):22046-22056. doi: 10.1039/d2cp02627a.
Group IVB transition metal (TM) nitrides rarely exhibit the semiconductor phase, except for TMN (TM = Ti, Zr, and Hf) compounds. In this study, using the calculations based on density functional theory, we report two chiral crystal structures, namely 321 and 321, of TMN, which are dynamically stable at ambient pressure. Unlike conventional metal phases of transition metal dinitrides, the 321 and 321 configurations exhibit intriguing semiconductor properties (with bandgaps of 1.076 eV, 1.341 eV, and 1.838 eV for TiN, ZrN, and HfN, respectively). The mechanism of metal-to-semiconductor transition from the 4/ to 321 phase is deeply explored by investigating their crystal structure and electronic structures. When hydrostatic pressure is applied from 0 GPa to 200 GPa, the bandgaps of the 321 phase of TiN, ZrN, and HfN exhibit a different response, which is related to the orbital contribution at the conduction band minimum (CBM) and valence band maximum (VBM) and the lattice constants. Furthermore, according to the calculated mechanical properties, 321 and 321 phases exhibit higher bulk and shear moduli than the semiconductor phases of c-ZrN and c-HfN in the corresponding systems.
除了TMN（TM = Ti、Zr和Hf）化合物外，IVB族过渡金属（TM）氮化物很少呈现半导体相。在本研究中，基于密度泛函理论进行计算，我们报告了TMN的两种手性晶体结构，即321和321，它们在常压下是动态稳定的。与传统的过渡金属二氮化物的金属相不同，321和321构型表现出有趣的半导体性质（TiN、ZrN和HfN的带隙分别为1.076 eV、1.341 eV和1.838 eV）。通过研究它们的晶体结构和电子结构，深入探讨了从4/相到321相的金属-半导体转变机制。当从0 GPa施加静水压力到200 GPa时，TiN、ZrN和HfN的321相的带隙表现出不同的响应，这与导带最小值（CBM）和价带最大值（VBM）处的轨道贡献以及晶格常数有关。此外，根据计算出的力学性能，321和321相在相应体系中表现出比c-ZrN和c-HfN的半导体相更高的体模量和剪切模量。
