Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES

TL;DR

This study uses high-resolution ARPES to analyze the temperature-dependent electronic structure of SmB6, revealing a wide-range Kondo hybridization process and persistent topological surface states across the resistivity anomaly.

Contribution

It provides a detailed temperature-dependent analysis of surface states and hybridization in SmB6, clarifying the Kondo crossover and its link to topological surface states.

Findings

Surface states are present both below and above the resistivity anomaly.

Quasi-particle scattering rate increases linearly with temperature and binding energy.

Hybridization between d and f states develops gradually over a wide temperature range.

Abstract

Temperature dependence of the electronic structure of SmB6 is studied by high-resolution ARPES down to 1 K. We demonstrate that there is no essential difference for the dispersions of the surface states below and above the resistivity saturating anomaly (~ 3.5 K). Quantitative analyses of the surface states indicate that the quasi-particle scattering rate increases linearly as a function of temperature and binding energy, which differs from Fermi-Liquid behavior. Most intriguingly, we observe that the hybridization between the d and f states builds gradually over a wide temperature region (30 K < T < 110 K). The surface states appear when the hybridization starts to develop. Our detailed temperature-dependence results give a complete interpretation of the exotic resistivity result of SmB6, as well as the discrepancies among experimental results concerning the temperature regions in which the topological surface states emerge and the Kondo gap opens, and give new insights into the exotic Kondo crossover and its relationship with the topological surface states in the topological Kondo insulator SmB6.