Non-Fermi-liquid d-wave metal phase of strongly interacting electrons

TL;DR

This paper introduces a theoretical model for a non-Fermi-liquid 'd-wave metal' phase in strongly interacting electrons, providing insights into strange metal behaviour observed in high-temperature superconductors.

Contribution

The authors develop a microscopic Hamiltonian and demonstrate, through variational, gauge theoretic, and DMRG methods, that it hosts a non-Fermi-liquid d-wave metal ground state.

Findings

Identified a realistic microscopic model hosting a non-Fermi-liquid phase.

Used advanced computational methods to confirm the phase's stability.

Provided a concrete example relevant to high-temperature superconductor physics.

Abstract

Developing a theoretical framework for conducting electronic fluids qualitatively distinct from those described by Landau's Fermi-liquid theory is of central importance to many outstanding problems in condensed matter physics. One such problem is that, above the transition temperature and near optimal doping, high-transition-temperature copper-oxide superconductors exhibit `strange metal' behaviour that is inconsistent with being a traditional Landau Fermi liquid. Indeed, a microscopic theory of a strange-metal quantum phase could shed new light on the interesting low-temperature behaviour in the pseudogap regime and on the d-wave superconductor itself. Here we present a theory for a specific example of a strange metal---the 'd-wave metal'. Using variational wavefunctions, gauge theoretic arguments, and ultimately large-scale density matrix renormalization group calculations, we show that this remarkable quantum phase is the ground state of a reasonable microscopic Hamiltonian---the usual t-J model with electron kinetic energy $t$ and two-spin exchange $J$ supplemented with a frustrated electron `ring-exchange' term, which we here examine extensively on the square lattice two-leg ladder. These findings constitute an explicit theoretical example of a genuine non-Fermi-liquid metal existing as the ground state of a realistic model.