压力对有机半导体均苯四甲酸晶体结构转变和电子性质的影响
Effect of pressure on the structure transitions and electronic properties of the organic semiconducting benzene tetracarboxylic acid crystal
龚智诚 1陈丽敏 1张超 1刘春生1
作者信息
- 1. 南京邮电大学 先进电磁信息材料与器件研究中心,南京 210023
- 折叠
摘要
研究高压条件下均苯四甲酸(C10H6O8)材料的结构和性质对探索有机半导体材料的应用有积极意义.基于密度泛函理论的第一性原理赝势平面波方法,开展了0-300 GPa压强下C10H6O8 晶体的结构、电子和光学性质的研究.晶格常数在压强20 GPa和150 GPa下出现了明显跳变,且原子之间随着压强变化反复地出现成键/断键现象,表明压强可诱导晶体结构变化.电子结构的性质表明,0 GPa的C10H6O8 晶体是带隙为3.1 eV的直接带隙半导体,而压强增加到150 GPa时,带隙突变为0 eV,表明了晶体由半导体转变为导体.当压强为160 GPa时,晶体又变成了能隙约为1eV的间接带隙半导体,这可能是费米能级附近仅受O-2p轨道电子影响所导致.通过对C10H6O8晶体介电函数的分析,再次验证了晶体在150 GPa时发生了结构相变.同时,电导率随压强增大而增强的特征表明,随压强增加,晶体体积被压缩,导致单位体积中导电粒子数增多.
Abstract
The study of the structure and properties of Benzenetetracarboxylic acid(C10H6O8)under high pres-sures is of positive significance to explore the application of organic semiconductor materials.Based on the first principle pseudo-potential plane wave method of density functional theory,the structural,electronic and optical properties of C10H6O8 crystal at 0-300 GPa are calculated.The lattice constants show the obvious jumps at the pressures of 20 GPa and 150 GPa,and the bonds between the atoms are formed/broken repeatedly with pressure increases,indicating that the pressure can induce the change of the crystal structure.The properties of the elec-tronic structure show that the C10H6O8 crystal is a direct bandgap semiconductor at 0 GPa,while the band gap decreases to 0 eV at 150 GPa,which indicate that the crystal transforms from the semiconductor state to the con-ductor state.When the pressure is 160 GPa,the crystal becomes an indirect band-gap semiconductor with an energy gap of about 1eV,which may be caused by the influence of the O-2p orbital electrons near the Fermi level.By analyzing the dielectric function of C10H6O8 crystal,it is again verified that the structural phase transi-tion occurs at 150 GPa.At the same time,the characteristic that the crystal conductivity increases with the in-crease of pressure shows that the crystal volume is compressed as the pressure increases,resulting in an increase in the number of conductive particles per unit volume.
关键词
C10H6O8/第一性原理/高压调控/电子结构/光学性质Key words
C10H6O8/First principle/High pressure control/Electronic structure/Optical properties引用本文复制引用
基金项目
国家自然科学基金(61971229)
国家自然科学基金(61974068)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据