# Strange metal state near a heavy-fermion quantum critical point

## TL;DR

This paper proposes a theoretical mechanism explaining the strange metal state observed near a heavy-fermion quantum critical point, addressing non-Fermi liquid behaviors through a competition between RVB spin-liquid fluctuations and Kondo correlations.

## Contribution

It introduces a field-theoretical renormalization group analysis of an effective model to explain the strange metal phenomena near quantum criticality in heavy-fermion systems.

## Key findings

- Identifies the critical point via RG analysis.
- Explains T-linear resistivity and specific heat anomalies.
- Describes crossover behaviors in the strange metal region.

## Abstract

Recent experiments on quantum criticality in the Ge-substituted heavy-electron material YbRh2Si2 under magnetic field have revealed a possible non-Fermi liquid (NFL) strange metal (SM) state over a finite range of fields at low temperatures, which still remains a puzzle. In the SM region, the zero-field antiferromagnetism is suppressed. Above a critical field, it gives way to a heavy Fermi liquid with Kondo correlation. The T (temperature)-linear resistivity and the T-logarithmic followed by a power-law singularity in the specific heat coefficient at low T, salient NFL behaviours in the SM region, are un-explained. We offer a mechanism to address these open issues theoretically based on the competition between a quasi-2d fluctuating short-ranged resonant- valence-bonds (RVB) spin-liquid and the Kondo correlation near criticality. Via a field-theoretical renormalization group analysis on an effective field theory beyond a large-N approach to an anti- ferromagnetic Kondo-Heisenberg model, we identify the critical point, and explain remarkably well both the crossovers and the SM behaviour.