A strange metal with a small Fermi surface and strong collective excitations

TL;DR

This paper proposes a hybrid state in a strongly correlated system where quasi-particles coexist with collective excitations, featuring an unconventional Fermi surface volume unrelated to electron density, emerging from coupled 1D Mott insulators.

Contribution

It introduces a novel hybrid state model with a small Fermi surface and strong collective modes, derived from coupled 1D Mott insulators, and explores its phase transition properties.

Findings

Existence of a hybrid state with a small Fermi surface

Unconventional Fermi surface volume independent of electron density

Antiferromagnetic transition at low temperatures

Abstract

We develop a theory of a hybrid state, where quasi-particles coexist with strong collective modes, taking as a starting point a model of infinitely many 1D Mott insulators coupled by a weak interchain tunneling. This state exists at an intermediate temperature range and undergoes an antiferromagnetic phase transition at temperatures much smaller than the Mott-Hubbard gap. The most peculiar feature of the hybrid state is that the volume of the Fermi surface is unrelated to the electron density. We present a self-consistent derivation of the low energy effective action for our model.