Effect of chemical substitution and pressure on YbRh2Si2

TL;DR

This study investigates how chemical substitution and external pressure influence the magnetic and quantum critical properties of YbRh2Si2, revealing how these factors can tune the system to a quantum critical point.

Contribution

It provides a comparative analysis of the effects of chemical substitution and external pressure on YbRh2Si2's ground state and quantum critical behavior.

Findings

External magnetic field suppresses T_N to zero at 60 mT.

Pressure stabilizes magnetic order, increasing T_N.

Chemical substitution can induce a pressure-controlled QCP.

Abstract

We carried out electrical resistivity experiments on (Yb,La)Rh2Si2 and on Yb(Rh,Ir)2Si2 under pressure and in magnetic fields. YbRh2Si2 exhibits a weak antiferromagnetic transition at atmospheric pressure with a N\'eel temperature of only T_N = 70 mK. By applying a small magnetic field T_N can be continuously suppressed to T=0 at B_c = 60 mT (B_|_c) driving the system to a quantum critical point (QCP). On applying external pressure the magnetic phase is stabilized and T_N(p) is increasing as usually observed in Yb-based heavy-fermion metals. Substituting Yb by La or Rh by Ir allows to create a negative chemical pressure, La (Ir) being smaller than Yb (Rh), and eventually to drive YbRh2Si2 to a pressure controlled QCP. In this paper we compare the effect of external hydrostatic pressure and chemical substitution on the ground-state properties of YbRh2Si2.