Quantum antiferromagnetism and high Tc superconductivity: A close connection between the t−J model and the projected BCS Hamiltonian

K. Park

doi:10.1103/PhysRevB.72.245116

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Quantum antiferromagnetism and high Tc superconductivity: A close connection between the t−J model and the projected BCS Hamiltonian

K. Park

DOI 10.1103/PhysRevB.72.245116 · Physical Review B

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Abstract

A connection between quantum antiferromagnetism and high Tc superconductivity is theoretically investigated by analyzing the t−J model and its relationships to the Gutzwiller-projected BCS Hamiltonian. After numerical corroboration via exact diagonalization, it is analytically shown that the ground state of the t−J model at half filling [i.e., the two-dimensional (2D) antiferromagnetic Heisenberg model] is entirely equivalent to the ground state of the Gutzwiller-projected BCS Hamiltonian with strong pairing. Combined with the high wave function overlap between the ground states of the t−J model and the projected BCS Hamiltonian at moderate doping, this equivalence provides strong support for the existence of superconductivity in the t−J model. The relationship between the ground state of the projected BCS Hamiltonian and Anderson’s resonating valence bond state (i.e., the projected BCS ground state) is discussed.