Andreev reflections in the pseudogap state of cuprate supercondcutors

Abstract

We propose that, if the pseudogap state in the cuprate superconductors can be described in terms of the phase-incoherent preformed pairs, there should exist Andreev reflection from these pairs even above the superconducting transition temperature, $T_c$. After giving qualitative arguments for this effect, we present more quantitative calculations based on the Bogoliubov--de Gennes equation. Experimental observations of the effects of Andreev reflections above $T_c$---such as an enhanced tunneling conductance below the gap along the copper oxide plane---could provide unambiguous evidence for the preformed pairs in the pseudogap state.

5 pages, 1 figure

References in corpus (5)

• The pseudogap in high-temperature superconductors: an experimental survey
• Vanishing of phase coherence in underdoped Bi_2Sr_2CaCu_2O_8+d
• Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates
• Magnetic field independence of the spin gap in YBa_2Cu_3O_{7-delta}
• Pseudogaps in Underdoped Cuprates

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• In-plane Tunneling Spectrum into a [110]-Oriented High-$T_c$ Superconductor in the Pseudogap Regime