Effect of pressure on the structure transitions and electronic properties of the organic semiconducting benzene tetracarboxylic acid crystal
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.
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维普
