Possible propagation of the Zhang–Rice singlet as a probable Cooper channel in the CuO2 planes

Abstract

The issue of how superconductivity originate in the CuO 2 planes believed to be crucial to understanding the high T c superconducting cuprates is still an going debate. In the wake of recent experimental observations of the the Zhang-Rice singlet (ZRS), its formation and propagation need to be revisited especially by using a simple approach almost at a phenomenological level. Within a highly simplified correlated variational approach (HSCVA) in this paper, a new formation of the ZRS as constituting the ground state of a single-band t-J model of the CuO 2 planes is developed.This formation is then used to demonstrate how the ZRS can be propagated as a probable Cooper channel in the CuO 2 planes.

A Possible Fundamental Theory of Cooper Pair Formation in Unconventional Superconductivity

“…A general answer to this question can be achieved by providing a quantitative and qualitative structure model of the CPF possible in all superconducting materials. In this current study, we have shown that at short distances, the CPF formation is by a nonlinear, nonlocal and nonhamiltonian strong hadronic-type interactions due to deep wave-overlapping of spinning particles leading to Hulthen potential that is attractive between two electrons in singlet couplings [20,21,29] while at large distance the CPF is by superexchange interaction which is purely a quantum mechanical affairs [23,26,30]. We observe that for both distances the control parameter responsible for the superconducting state is the effective valence z.…”

“…Zhang and Rice generalized the Anderson approach by showing that it is possible to obtain the Cooper pair as a bound singlet state of the CuO 2 plane within a t-J model [49]. This singlet state now commonly known as the Zhang-Rice singlet (ZRS) which is the Cooper pair of the superconducting cuprates has been achieved [23] by the quantum mechanical superexchange interaction using the first electron removal (FER) approach [50] and a highly simplified correlated variational approach [51] to obtain a t-J model with the interaction part, J being the XY limit of the anisotropic Heisenberg exchange interaction in second quantization language:…”