Magnetic field tuned quantum criticality of heavy fermion system YbPtBi

TL;DR

This study investigates the magnetic field-driven quantum criticality in YbPtBi, revealing a suppression of antiferromagnetic order and the emergence of distinct low-temperature states, including a potential spin liquid, through comprehensive thermodynamic and transport measurements.

Contribution

It provides the first detailed phase diagram of YbPtBi under magnetic fields, identifying a field-tuned quantum critical point and novel low-temperature states.

Findings

Antiferromagnetic order suppressed at ~4 kOe

Observation of a non-Fermi liquid state with T^{1.5} resistivity

Identification of a Fermi liquid state with T^{2} resistivity at higher fields

Abstract

In this paper, we present the systematic measurements of the temperature and magnetic field dependences of the thermodynamic and transport properties of the Yb-based heavy fermion YbPtBi for temperatures down to 0.02 K with magnetic fields up to 140 kOe to address the possible existence of a field-tuned quantum critical point. Measurements of magnetic field and temperature dependent resistivity, specific heat, thermal expansion, Hall effect, and thermoelectric power indicate that the AFM order can be suppressed by applied magnetic field of $H_{c}$ $\sim$ 4 kOe. In the $H-T$ phase diagram of YbPtBi, three regimes of its low temperature states emerges: (I) AFM state, characterized by spin density wave (SDW) like feature, which can be suppressed to $T$ = 0 by the relatively small magnetic field of $H_{c}$ $\sim$ 4\,kOe, (II) field induced anomalous state in which the electrical resistivity follows $\Delta\rho(T) \propto T^{1.5}$ between $H_{c}$ and $\sim$ 8 kOe, and (III) Fermi liquid (FL) state in which $\Delta\rho(T) \propto T^{2}$ for $H \geq$ 8 kOe. Regions I and II are separated at $T$ = 0 by what appears to be a quantum critical point. Whereas region III appears to be a FL associated with the hybridized 4$f$ states of Yb, region II may be a manifestation of a spin liquid state.