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Modern Physics Letters B

ATTRACTIVE CORRELATED ELECTRON-PAIR GROUND STATE OF RESONANT BOSONS

B. K. Chakraverty

Published Jan 20, 1993• 1 citation
Publisher

Abstract

We consider a strictly one-band Hamiltonian of electrons with attractive interaction between them. We show that in the interesting intermediate density regime, where V ≤ ε F , the system admits a mixed state of free fermions and dynamic correlated pairs or resonant bosons. The inevitable coupling between the two sub-system produces a superconducting ground state. This should be called Schafroth Condensation.

DOI
10.1142/s0217984993000138

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We present a formulation of the resonating-valence-bond theory of the large-UUU one-band Hubbard model in two dimensions, in which the correlated ground state of the system is represented as a fluid of mobile singlet bonds. We describe this fluid as a quantum fluid of interacting hardcore bosons, and a ground-state wave function for the interacting bosons is studied in which two-body correlations are introduced by applying techniques previously developed in Laughlin's theory of the fractional quantum Hall problem. The resulting many-particle state in this formulation exhibits an incipient momentum space condensation and a class of particlelike excitations in the form of quantized vortices which possess fractional particle number, and interesting dynamics. Application of this model to the doped state reveals a mechanism by which the electrostatic repulsive interactions between the charged quasiparticles in the doped fluid stabilize the resonating state relative to the doped N\'eel state at discrete well-correlated "commensurate" hole concentrations. A superconducting state in this doped fluid arises from a condensation which pairs the charged quasiparticles; it is identified as the most stable of a hierarchy of possible condensed quasiparticle states. The condensed state exhibits many properties associated with conventional superconductivity, including dissipationless flow of current, Meissner effect, and flux quantization in units of hc2e\frac{\mathrm{hc}}{2e}2ehc​.