Field-induced gap, pseudogap and new Van Hove singularity in the triangular latticeY. F. Wang1, C. D. Gong2, 3 and S. Y. Zhu3
1 National Laboratory of Solid State Microstructures, Department of Physics Nanjing University, Nanjing 210093, PRC
2 Chinese Center of Advanced Science and Technology (World Laboratory) P.O. Box 8730, Beijing 100080, PRC
3 Department of Physics, Hong Kong Baptist University Kowloon Tong, Hong Kong, PRC
received 27 September 2004; accepted in final form 22 November 2004
published online 7 January 2005
We investigate the energy spectrum and the density of states (DOS) in a 2D triangular tight-binding model with hopping integrals modulated by staggered magnetic fluxes (SMFs). Three different types of SMFs are considered. The SMFs result in shifts of the original Van Hove singularity (VHS) peak in the DOS, or even generate new flux-dependent VHSs. And a gap or a pseudogap can also be generated on the original Fermi surface. The magnitude of the pseudogap or the gap and its symmetries depend on the chemical potential , and on the flux parameters.
71.20.-b - Electron density of states and band structure of crystalline solids.
71.30.+h - Metal-insulator transitions and other electronic transitions.
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