Two-gap model for underdoped cuprate superconductors
摘要
Various properties of underdoped superconducting cuprates, including the momentum-dependent pseudogap opening, indicate a behavior which is neither BCS nor Bose-Einstein condensation (BEC) like. To explain this issue we introduce a two-gap model. This model assumes an anisotropic pairing interaction among two kinds of fermions with small and large Fermi velocities representing the quasiparticles near the M and the nodal points of the Fermi surface respectively. We find that a gap forms near the M points resulting into incoherent pairing due to strong fluctuations. Instead the pairing near the nodal points sets in with phase coherence at lower temperature. By tuning the momentum-dependent interaction, the model allows for a continuous evolution from a pure BCS pairing (in the overdoped and optimally doped regime) to a mixed boson-fermion picture (in the strongly underdoped regime).
引用
@article{arxiv.cond-mat/9912363,
title = {Two-gap model for underdoped cuprate superconductors},
author = {A. Perali and C. Castellani and C. Di Castro and M. Grilli and E. Piegari and A. A. Varlamov},
journal= {arXiv preprint arXiv:cond-mat/9912363},
year = {2009}
}
备注
5 pages, 1 enclosed figure. For further information see http://htcs.org