Unconventional resistivity at the border of metallic antiferromagnetism in NiS2

TL;DR

This study investigates the resistivity behavior of NiS_2 under high pressure, revealing unconventional resistivity scaling near the suppression of antiferromagnetism, with differences attributed to disorder and spin fluctuations.

Contribution

It provides new insights into resistivity scaling and spin-fluctuation effects at the antiferromagnetic quantum critical point in NiS_2.

Findings

Resistivity follows approximately T^{1.5} near the critical pressure.

Resistivity exhibits undulating temperature dependence not seen in NiSSe.

Differences attributed to spin-fluctuation scattering and disorder effects.

Abstract

We report low-temperature and high-pressure measurements of the electrical resistivity \rho(T) of the antiferromagnetic compound NiS_2 in its high-pressure metallic state. The form of \rho(T) suggests that metallic antiferromagnetism in NiS_2 is quenched at a critical pressure p_c=76+-5 kbar. Near p_c the temperature variation of \rho(T) is similar to that observed in NiS_{2-x}Se_x near the critical composition x=1 where the Neel temperature vanishes at ambient pressure. In both cases \rho(T) varies approximately as T^{1.5} over a wide range below 100 K. However, on closer analysis the resistivity exponent in NiS_2 exhibits an undulating variation with temperature not seen in NiSSe (x=1). This difference in behaviour may be due to the effects of spin-fluctuation scattering of charge carriers on cold and hot spots of the Fermi surface in the presence of quenched disorder, which is higher in NiSSe than in stoichiometric NiS_2.