Heavy surface state in a possible topological Kondo insulator: Magneto-thermoelectric transport on the (011)-plane of SmB$_6$

TL;DR

This study investigates the magneto-thermoelectric properties of the (011) surface of SmB$_6$, revealing a heavy metallic surface state likely influenced by electronic correlations, supporting its classification as a topological Kondo insulator.

Contribution

First measurement of thermopower and Nernst effect on the (011) surface of SmB$_6$, demonstrating a heavy metallic surface state distinct from the bulk.

Findings

Surface exhibits a metallic state with effective mass 10-10^2 m_0.

Surface and bulk conductances are distinguishable and categorized.

Electronic correlations enhance scattering and contribute to the heavy surface state.

Abstract

Motivated by the high sensitivity to Fermi surface topology and scattering mechanisms in magneto-thermoelectric transport, we have measured the thermopower and Nernst effect on the (011)-plane of the proposed topological Kondo insulator SmB$_6$. These experiments, together with electrical resistivity and Hall effect measurements, demonstrate that the (011)-plane also harbors a metallic surface with the effective mass in the order of 10-10$^2$ $m_0$. The surface and bulk conductances are well distinguished in these measurements and are categorized into metallic and non-degenerate semiconducting regimes, respectively. Electronic correlations play an important role in enhancing scattering and also contribute to the heavy surface state.