Evolution of hyperfine parameters across a quantum critical point in CeRhIn$_5$

TL;DR

This study uses NMR to investigate how hyperfine interactions in CeRhIn$_5$ evolve under pressure, revealing electronic structure changes at a quantum critical point around 1.75 GPa.

Contribution

First detailed NMR analysis of hyperfine parameters across a quantum critical point in CeRhIn$_5$ under pressure.

Findings

Suppression of hyperfine coupling to In(1) site with pressure.

Change in slope of electric field gradient at In(2) site at P_c1=1.75 GPa.

Alterations in electronic structure at the quantum critical point.

Abstract

We report Nuclear Magnetic Resonance (NMR) data for both the In(1) and In(2) sites in the heavy fermion material CeRhIn$_5$ under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient, $\nu_{\alpha\alpha}$, at the In(2) site exhibits a change of slope, $d\nu_{\alpha\alpha}/dP$, at $P_{c1} = 1.75$ GPa. These changes to these coupling constants reflect alterations to the electronic structure at the quantum critical point.