摘要
结合粒子群优化算法生成的候选结构和第一性原理的稳定性分析,预测出新型B-C-O化合物B_(4)C_(6)O_(4)。B_(4)C_(6)O_(4)具有带隙宽度约2.25 eV的直接带隙半导体属性。研究同属BC_(x)O系列,且结构具有相似性的B_(4)C_(6)O_(4)、B_(2)CO_(2)和B_(4)CO_(4),发现C含量的降低会导致体系带隙增大,三者的分子式体积随C含量的降低而降低,且100 GPa的高压对三者体积均形成高达20%的压缩。高压导致B_(2)CO_(2)和B_(4)C_(6)O_(4)的带隙持续降低,而B_(4)CO_(4)的带隙先升后降。应力-应变模拟结果表明,3种BC_(x)O(x=3/2,1/2,1/4)化合物均具有较高的极限拉伸应力,同时应力引起的应变会影响3种BC_(x)O化合物的带隙。力学性能研究表明,3种BC_(x)O化合物均具有高弹性模量和高硬度等特点。常压下BC_(x)O的最高声子振动频率均高于30 THz,且由高到低分别为B_(4)CO_(4)、B_(2)CO_(2)、B_(4)C_(6)O_(4),压力作用使该体系结构的键能持续增强。
A novel B-C-O compound,B_(4)C_(6)O_(4),was predicted by combining the candidate structure generated by the particle swarm optimization algorithm and first-principles stability analysis.B_(4)C_(6)O_(4)has a direct bandgap semiconductivity characteristic with a bandgap width of about 2.25 eV.B_(4)C_(6)O_(4),B_(2)CO_(2)and B_(4)CO_(4)have similar structures and belong to the BC_(x)O series.It was found that the decrease of carbon content led to the increase of the band gap of the system,and the molecular formula volume decreased synchronically with the decrease of carbon content,and the high pressure of 100 GPa compressed the volume of the three as high as 20%.The band gaps of B_(2)CO_(2)and B_(4)C_(6)O_(4)continue to decrease due to the effect of high pressure,while the band gap of B_(4)CO_(4)rise first and then fall.The stress-strain simulation results showed that the three BC_(x)O compounds(x=3/2,1/2,1/4)all have high ultimate tensile stress,and the strain would affect the band gaps of the three BC_(x)O compounds.The mechanical properties of three BC_(x)O compounds showed that they all had high modulus of elasticity and hardness.The highest phonon vibration frequencies of BC_(x)O under chamber pressure are higher than 30 THz,and the relationship is B_(4)CO_(4)>B_(2)CO_(2)>B_(4)C_(6)O_(4).The effect of high pressure will cause the continuous enhancement of the bond energy of the system.
作者
刘超
应盼
LIU Chao;YING Pan(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,Hebei,China;Hebei Key Laboratory of Microstructural Material Physics,School of Science,Yanshan University,Qinhuangdao 066004,Hebei,China)
出处
《高压物理学报》
CAS
CSCD
北大核心
2021年第6期37-49,共13页
Chinese Journal of High Pressure Physics
基金
国家自然科学基金(12064013)
江西省自然科学基金(20202BAB214010)
亚稳材料制备技术与科学国家重点实验室开放课题(201906)
赣州市科技创新人才计划(202060)
江西理工大学清江青年优秀人才支持计划(JXUSTQJYX2020002)。
关键词
高压
碳含量
稳定性
力学性质
电学性质
high pressure
carbon content
stability
mechanical properties
electrical properties
