# Spintronic signatures of Klein tunneling in topological insulators

## TL;DR

This paper proposes a new electrical detection method for Klein tunneling in topological insulators, utilizing spin-momentum locking and ferromagnetic probes to observe distinctive signatures in transport measurements.

## Contribution

It introduces a practical approach to detect Klein tunneling in topological insulator PN junctions through electrical measurements of spin texture and angular dependence.

## Key findings

- Asymmetry in potentiometric signals indicates Klein tunneling.
- Angular dependence of signals serves as a direct signature.
- Electrical detection method is feasible for topological insulators.

## Abstract

Klein tunneling, the perfect transmission of normally incident Dirac electrons across a potential barrier, has been widely studied in graphene and explored to design switches, albeit indirectly. We show that Klein tunneling maybe easier to detect for spin-momentum locked electrons crossing a PN junction along a three-dimensional topological insulator surface. In these topological insulator PN junctions (TIPNJs), the spin texture and momentum distribution of transmitted electrons can be measured electrically using a ferromagnetic probe for varying gate voltages and angles of current injection. Based on transport models across a TIPNJ, we show that the asymmetry in the potentiometric signal between PP and PN junctions and its overall angular dependence serve as a direct signature of Klein tunneling.