Effects of general non-magnetic quenched disorder on a spin-density-wave quantum critical metallic system in two spatial dimension

TL;DR

This paper studies how non-magnetic quenched disorder affects a two-dimensional spin-density-wave quantum critical metal, revealing complex RG flow behaviors and potential phases beyond the clean non-Fermi liquid state.

Contribution

It provides a comprehensive RG analysis of disorder effects on SDW quantum critical metals, including one-loop and two-loop corrections, and explores the stability of fixed points and low-energy phases.

Findings

Weakly disordered non-Fermi liquid fixed point identified

No stable fixed point when all disorder channels are considered

Large random charge potential dominates low-energy RG flows

Abstract

We investigate the effects of general non-magnetic quenched disorder on a two-dimensional spin-density-wave (SDW) quantum critical metallic system and discuss how a clean SDW non-Fermi liquid state becomes modified, based on a renormalization group (RG) method. We consider (i) all possible scattering channels by a random charge potential for fermion fields and additionally (ii) a random mass term for a SDW boson order parameter as effects of the non-magnetic quenched disorder. From the one-loop analysis, we find a weakly disordered non-Fermi liquid metallic fixed point(interacting long-range ordered fixed point) when only the random boson mass vertex is considered. However, in the general case where all disorder vertices are considered, it turns out that there is no stable fixed point and the low-energy RG flows are governed by the large random charge potential vertices especially channels in a `Direct' category with an interplay of an effective Yukawa interaction. Focusing on the physical meanings of the low-energy RG flows, we provide a detailed explanation of the one-loop results. Beyond the one-loop level, we first discuss partial two-loop corrections to the random charge potential vertices. Furthermore, we examine the possibility of different low-energy RG flows compared to that of the one-loop results by considering the two-loop corrections to the random boson mass vertex and, discuss low energy properties in relation to the random singlet phase. For physical properties, we calculate asymptotic forms of the two-point Green's functions and anomalous dimensions of the four superconducting channels in the one-loop level.