高压物理学报2024，Vol.38Issue(4)：34-43,10.DOI:10.11858/gywlxb.20240719
K2N2中一维氮链的压力诱导聚合
Pressure-Induced Polymerization of One-Dimensional Nitrogen Chains in K2N2
摘要
Abstract
The crystal structure prediction of K2N2 in the pressure range of 0-150 GPa using an advanced particle swarm crystal structure search method was conducted.The results show that the stable ground state phase of K2N2 is a monoclinic C2/m structure,and three high-pressure structures including Na2N2-type,Cmmm,and C2/c are identified at pressures of 1.7,3.6,122 GPa,respectively.The volume dependence on pressure shows that the three phase transitions,i.e.,C2/m→Na2N2-type,Na2N2-type→Cmmm,and Cmmm→C2/c,are all first order phase transitions,corresponding to volume collapses of 14.4%,22.5%,and 4.0%,respectively.During the high pressure phase transitions of K2N2,the coordination number of K atom increases from 5 to 10,and a change in the nature of the N-N bonding from N=N dimmer in the ground state of C2/m structure to N―N single bond chain in the high-pressure C2/c phase is accompanied.The high-pressure C2/c phase exhibits semiconducting properties with a band gap of 2.0 eV,while C2/m,Na2N2-type,and Cmmm phases have metallic behaviors.Electronic structure calculation and electron-localized function analysis indicate that the high-pressure structural phase transition of K2N2 is due to the K-p lone-pair electrons activation and their participation in bonding with N atoms under high pressure.关键词
高压/K2N2/结构预测/结构相变/电子结构Key words
high pressure/K2N2/structure predictions/phase transitions/electronic structures分类
数理科学引用本文复制引用
陈磊,张云,陈雨轩,魏群,张美光..K2N2中一维氮链的压力诱导聚合[J].高压物理学报,2024,38(4):34-43,10.基金项目
National Natural Science Foundation of China(11964026) （11964026）
Natural Science Basic Research Program of Shaanxi(2023-JC-YB-021,2024JC-YBMS-048) （2023-JC-YB-021,2024JC-YBMS-048）
