Kinetic-energy driven superconductivity in cuprate superconductors

TL;DR

This paper reviews a kinetic-energy driven superconductivity mechanism in cuprates, emphasizing purely electronic interactions via spin excitations that explain the doping-dependent superconducting and pseudogap states.

Contribution

It introduces a novel kinetic-energy based pairing mechanism driven by spin excitations, distinct from phonon-mediated theories, explaining key features of cuprate superconductivity.

Findings

Superconductivity arises from kinetic energy and spin excitations.

Maximal Tc occurs near optimal doping, decreasing in underdoped and overdoped regimes.

The pseudogap state is linked to the same spin-mediated interactions.

Abstract

Superconductivity in cuprate superconductors occurs upon charge-carrier doping Mott insulators, where a central question is what mechanism causes the loss of electrical resistance below the superconducting (SC) transition temperature? In this review, we attempt to summarize the basic idea of the kinetic-energy driven SC mechanism in the description of superconductivity in cuprate superconductors. The mechanism of the kinetic-energy driven superconductivity is purely electronic without phonons, where the charge-carrier pairing interaction arises directly from the kinetic energy by the exchange of spin excitations in the higher powers of the doping concentration. This kinetic-energy driven d-wave SC-state is controlled by both the SC gap and quasiparticle coherence, which leads to that the maximal SC transition temperature occurs around the optimal doping, and then decreases in both the underdoped and overdoped regimes. In particular, the same charge-carrier interaction mediated by spin excitations that induces the SC-state in the particle-particle channel also generates the normal-state pseudogap state in the particle-hole channel. The normal-state pseudogap crossover temperature is much larger than the SC transition temperature in the underdoped and optimally doped regimes, and then monotonically decreases upon the increase of doping, eventually disappearing together with superconductivity at the end of the SC dome. This kinetic-energy driven SC mechanism also indicates that the strong electron correlation favors superconductivity, since the main ingredient is identified into a charge-carrier pairing mechanism not from the external degree of freedom such as the phonon but rather solely from the internal spin degree of freedom of the electron. The typical properties of cuprate superconductors discussed within the framework of the kinetic-energy driven SC mechanism are also reviewed.