Non-interacting Cooper pairs inside a pseudogap

Дата и время публикации : 1997-05-13T21:08:40Z

Авторы публикации и институты :
O. Tchernyshyov

Ссылка на журнал-издание: Phys.Rev.B 56, 3372 (1997)
Коментарии к cтатье: LaTeX (prbbib.sty included), 24 pages, 4 PostScript figures To appear in Phys.Rev.B
Первичная категория: cond-mat.supr-con

Все категории : cond-mat.supr-con

Краткий обзор статьи: I present a simple analytical model describing the normal state of a superconductor with a pseudogap in the density of states, such as in underdoped cuprates. In nearly two-dimensional systems, where the superconducting transition temperature is reduced from the mean-field BCS value, Cooper pairs may be present as slow fluctuations of the BCS pairing field. Using the self-consistent T-matrix (fluctuation exchange) approach I find that the fermion spectral weight exhibits two BCS-like peaks, broadened by fluctuations of the pairing field amplitude. The density of states becomes suppressed near the Fermi energy, which allows for long-lived low-energy Cooper pairs that propagate as a sound-like mode with a mass. A self-consistency requirement, linking the width of the pseudogap to the intensity of the pairing field, determines the pair condensation temperature. In nearly two-dimensional systems, it is proportional to the degeneracy temperature of the fermions, with a small prefactor that vanishes in two dimensions.

Category: Physics