Anharmonicity in One-Dimensional Electron-Phonon System

作者：Zhao, Jize^*; Ueda, Kazuo

来源：Journal of the Physical Society of Japan, 2010, 79(7): 074602.

DOI：10.1143/JPSJ.79.074602

• anharmonicity
• Holstein model
• electron-phonon interaction
• dimerization
• charge density wave

We investigate the effect of anharmonicity on the one-dimensional half-filled Holstein model by using the determinant quantum Monte Carlo method. By calculating the order parameters, we find that with and without anharmonicity, there is always a transition from a disorder phase to a dimerized phase. Moreover, in the dimerized phase, a lattice dimerization and a charge density wave coexist. The anharmonicity represented by the quartic term suppresses the dimerization as well as the charge density wave, while a double-well potential favors the dimerization. In addition, by calculating the correlation exponents, we show that the disorder phase is metallic with gapless charge and gapful spin excitations, and that both excitations are gapful in the dimerized phase.

• 出版日期2010-7
• 单位中国人民大学