The evidence of edge-gaps around the M-points in the metallic state of underdoped cuprates has triggered a very active debate on their origin. We first consider the possibility that this spectroscopic feature results from a quasi-static charge ordering taking place in the underdoped regime. It comes out that to explain the coexistence of gaps and arcs on the Fermi surface the charge modulation should be in an eggbox form. In the lack of evidences for that, we then investigate the local pairing induced by charge-stripe fluctuations. A proper description of the strong anisotropy of both the interactions and the Fermi velocities requires a two-gap model for pairing. We find that a gap due to incoherent pairing forms near the M-points, while coherence is established by the stiffness of the pairing near the nodal points. The model allows for a continuos evolution from a pure BCS pairing (over-and optimally doped regime) to a mixed boson-fermion model (heavily underdoped regime).
Stripe ordering and two-gap model for underdoped cuprates / Castellani, Claudio; DI CASTRO, Carlo; Grilli, Marco; A., Perali. - In: PHYSICA. C, SUPERCONDUCTIVITY. - ISSN 0921-4534. - 341:PART 2(2000), pp. 1739-1742. (Intervento presentato al convegno International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI tenutosi a HOUSTON, TEXAS nel FEB 20-25, 2000) [10.1016/s0921-4534(00)00965-5].
Stripe ordering and two-gap model for underdoped cuprates
CASTELLANI, Claudio;DI CASTRO, Carlo;GRILLI, Marco;
2000
Abstract
The evidence of edge-gaps around the M-points in the metallic state of underdoped cuprates has triggered a very active debate on their origin. We first consider the possibility that this spectroscopic feature results from a quasi-static charge ordering taking place in the underdoped regime. It comes out that to explain the coexistence of gaps and arcs on the Fermi surface the charge modulation should be in an eggbox form. In the lack of evidences for that, we then investigate the local pairing induced by charge-stripe fluctuations. A proper description of the strong anisotropy of both the interactions and the Fermi velocities requires a two-gap model for pairing. We find that a gap due to incoherent pairing forms near the M-points, while coherence is established by the stiffness of the pairing near the nodal points. The model allows for a continuos evolution from a pure BCS pairing (over-and optimally doped regime) to a mixed boson-fermion model (heavily underdoped regime).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
