Theoretical studies of electronic properties in graphene-related systems using Thermally-Assisted-Occupation density functional theory

• Main Authors: Chia-Cheng Huang, 黃家政
• Other Authors: 蔡政達
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/80186209380368037500

碩士 === 國立臺灣大學 === 物理研究所 === 100 === The electronic properties of fused-azulenes chain and graphene-like nanopatches have been probed by using the Thermally-Assisted-Occupation density functional theory (TAO-DFT) which is believed to have a correct treatment of such strong electronic correlation systems. The results in this study suggest that not only fused-azulenes but also graphene-patches show polyradical characteristics in their respec-tive polymeric limits, and also predict almost vanishing singlet-triplet states energy gaps of them by extrapolating the singlet-triplet states energy gap to their respective infine size limits. The theoretical calculation results of DFT provides a irregular trend of singlet-triplet energy gap curve for both fused-azulenes and grapehen-patches. We compared the singlet-triplet energy gap curves calculated by DFT and TAO-DFT, TAO-DFT provides a more reasonable and more smooth curve than DFT since TAO-DFT accurately describes the strong correlation effect and reduce the spin contamination effectively.