Fermi surface truncation from thermal nematic fluctuations

TL;DR

This paper investigates how thermal nematic fluctuations influence the spectral function in a 2D metal, revealing Fermi surface truncation into arcs rather than peak splitting.

Contribution

It presents a resummation approach showing that thermal fluctuations cause broadening and truncation of the Fermi surface, contrasting with previous pseudogap interpretations.

Findings

Spectral function broadens near the nematic transition.

Fermi surface appears truncated into arcs.

Broadening varies strongly around the Fermi surface.

Abstract

We analyze how thermal fluctuations near a finite temperature nematic phase transition affect the spectral function $A({\bf k},\omega)$ for single-electron excitations in a two-dimensional metal. Perturbation theory yields a splitting of the quasi-particle peak with a d-wave form factor, reminiscent of a pseudogap. We present a resummation of contributions to all orders in the Gaussian fluctuation regime. Instead of a splitting, the resulting spectral function exhibits a pronounced broadening of the quasi-particle peak, which varies strongly around the Fermi surface and vanishes upon approaching the Brillouin zone diagonal. The Fermi surface obtained from a Brillouin zone plot of $A({\bf k},0)$ seems truncated to Fermi arcs.