Cotunneling into a Kondo lattice with odd hybridization

TL;DR

This paper extends the theory of electron cotunneling to Kondo lattice systems with odd hybridization, revealing fundamental differences in interference effects compared to even hybridization, with implications for scanning-tunneling-spectroscopy experiments.

Contribution

It introduces a theoretical framework for cotunneling in Kondo lattices with odd hybridization, highlighting how interference effects differ from the even hybridization case, especially in layered and three-dimensional materials.

Findings

Interference between tunneling processes is absent in layered materials.

Energy dependence of tunneling is strongly modified in three-dimensional systems.

Implications for interpreting scanning-tunneling-spectroscopy data in Kondo insulators.

Abstract

Cotunneling into Kondo systems, where an electron enters a $f$-electron material via a cotunneling process through the local-moment orbital, has been proposed to explain the characteristic lineshapes observed in scanning-tunneling-spectroscopy (STS) experiments. Here we extend the theory of electron cotunneling to Kondo-lattice systems where the bulk hybridization between conduction and $f$ electrons is odd under inversion, being particularly relevant to Kondo insulators. Compared to the case of even hybridization, we show that the interference between normal tunneling and cotunneling processes is fundamentally altered: it is entirely absent for layered, i.e., quasi-two-dimensional materials, while its energy dependence is strongly modified for three-dimensional materials. We discuss implications for STS experiments.