Electronic transport in the Coulomb phase of the pyrochlore spin ice

TL;DR

This paper explores how electron transport in pyrochlore spin ice is affected by magnetic monopoles, revealing a non-monotonic resistivity behavior linked to spin correlations and monopole excitations, consistent with experimental data.

Contribution

It introduces a model connecting magnetic monopole excitations to electron scattering, explaining the resistivity minimum in metallic spin-ice compounds.

Findings

Residual resistivity at zero temperature due to static spin correlations.

Suppression of electron scattering by thermally excited magnetic monopoles.

Quantitative agreement with resistivity measurements in Nd2Ir2O7.

Abstract

We investigate the transport properties of itinerant electrons interacting with a background of localized spins in a correlated paramagnetic phase of the pyrochlore lattice. We find a residual resistivity at zero temperature due to the scattering of electrons by the static dipolar spin-spin correlation that characterizes the metallic Coulomb phase. As temperature increases, thermally excited topological defects, also known as magnetic monopoles, reduce the spin correlation, hence suppressing electron scattering. Combined with the usual scattering processes in metals at higher temperatures, this mechanism yields a non-monotonic resistivity, displaying a minimum at temperature scales associated with the magnetic monopole excitation energy. Our calculations agree quantitatively with resistivity measurements in Nd2Ir2O7, shedding light on the origin of the resistivity minimum observed in metallic spin-ice compounds.