Inverted Hanle spin precession induced magnetoresistance in chiral/semiconductor systems

TL;DR

This paper investigates the magnetoresistance effects in chiral/semiconductor systems, revealing that Hanle spin precession signals are inverted compared to ferromagnetic systems, providing insights into spin injection and detection mechanisms.

Contribution

It models and demonstrates that Hanle signals in chiral systems are the inverse of those in ferromagnetic systems, clarifying the microscopic origin of the effect.

Findings

Hanle signals in chiral systems are opposite to ferromagnetic systems.

Modeling shows the inversion of spin precession signals across systems.

Provides a detailed analysis of spin transport in chiral/semiconductor interfaces.

Abstract

In the past decade, chiral materials have drawn significant attention because it is widely claimed that they can act as spin injectors/detectors due to the chirality-induced spin selectivity (CISS) effect. Nevertheless, the microscopic origin of this effect is not understood, and there is an intensive discussion about the manifestation of the magnetoresistance that is generated between a chiral system and a ferromagnet. Hanle spin precession measurements can unambiguously prove the injection and detection of a spin accumulation in a non-magnetic material, as was shown with traditional ferromagnetic injectors/detectors. Here, we analyze in detail the Hanle spin precession induced magnetoresistance and find that it is inverted as compared to the ferromagnetic case. We explicitly model the spin injection and detection by both a chiral system and a ferromagnetic system, as well as the spin transport in a semiconductor, for a general set of (spin) transport parameters that cover the relevant experimental regime. For all sets of parameters, we find that the Hanle signals for a chiral system and ferromagnet are each others opposites.