Quantum criticality preempted by nematicity

TL;DR

This paper investigates how nematic order prevents the realization of a non-Fermi-liquid quantum critical point in 3D double-Weyl semimetals, highlighting the dominance of nematic phases due to Coulomb interactions.

Contribution

It reveals that nematic ordering preempts the expected quantum critical point in double-Weyl semimetals when Coulomb interactions are considered.

Findings

Non-Fermi-liquid QCP is unstable against nematic order.

Nematic phases emerge instead of the QCP in the presence of Coulomb interactions.

Potential relevance to materials HgCr2Se4 and SrSi2.

Abstract

Exotic physics often emerges around quantum criticality in metallic systems. Here we explore the nature of topological phase transitions between 3D double-Weyl semimetals and insulators (through annihilating double-Weyl nodes with opposite chiralities) in the presence of Coulomb interactions. From renormalization-group (RG) analysis, we find a non-Fermi-liquid quantum critical point (QCP) between the double-Weyl semimetals and insulators when artificially neglecting short-range interactions. However, it is shown that this non-Fermi-liquid QCP is actually unstable against nematic ordering when short-range interactions are correctly included in the RG analysis. In other words, the putative QCP between the semimetals and insulators is preempted by emergence of nematic phases when Coulomb interactions are present. We further discuss possible experimental relevance of the nematicity-preempted QCP to double-Weyl candidate materials HgCr2Se4 and SrSi2.