Non-Fermi liquid properties of 2d symplectic fermions: the role of a dynamically generated (pseudo)-gap

TL;DR

This paper investigates a 2D symplectic fermion model revealing a dynamically generated pseudogap that exhibits non-Fermi liquid behavior and impacts high-temperature superconductivity phenomena.

Contribution

It demonstrates the dynamical generation of a relativistic mass and pseudogap in a 2D symplectic fermion model, linking it to high-Tc superconductivity and pseudogap phenomena.

Findings

Relativistic mass m is dynamically generated in the model.

The pseudogap scale T* equals the zero-temperature mass m.

The model reproduces qualitative features of the pseudogap in high-Tc superconductors.

Abstract

The interacting symplectic fermion model in two spatial dimensions is further analyzed. As an effective low energy theory, the model is unitary. We show that a relativistic mass m is dynamically generated and derive a gap equation for it. By incorporating a finite temperature we study some fundamental properties of the model, such as the specific heat and spin response, which clearly show non-Fermi liquid properties. We find that various physical properties are suppressed at temperatures T< T* where the cross-over scale is T* = m. As a simplified, toy model of high Tc superconductivity, we thus identify the pseudogap energy scale with the zero temperature relativistic mass m, and show that this reproduces some qualitative aspects of the observed phenomenology of the pseudogap. The effects of the pseudogap and finite temperature on the d-wave gap equation are analyzed. In this model, the pseudogap is a distinct phenomenon from superconductivity and in fact competes with it. Our analysis of Tc suggests that the quantum critical point of our model, where the pseudogap vanishes, occurs inside the superconducting dome near optimal doping. For an antiferromagnetic exchange energy of J/k_B ~ 1350K, solutions of the d-wave gap equation give a maximum Tc of about 110K.