Electrical probe of spin-spiral order in quantum spin Hall/spin-spiral magnet van der Waals heterostructures

TL;DR

This paper demonstrates that electrical measurements in van der Waals heterostructures combining spin-spiral magnets and quantum spin Hall insulators can detect noncollinear magnetic order despite the absence of net magnetization, using helical state sensitivity.

Contribution

It introduces a novel electrical detection method for spin-spiral order in 2D heterostructures by exploiting the interaction between helical states and local magnetic textures.

Findings

Electrical signatures of spin-spiral order can be observed in transport measurements.

Scattering in helical channels correlates with spiral exchange coupling and disorder.

Detection is possible even without net magnetization due to local symmetry breaking.

Abstract

Two-dimensional spin-spiral magnets provide promising building blocks for van der Waals heterostructures due to their tunable spin textures and potential for novel functionalities for quantum devices. However, due to its vanishing magnetization and two-dimensional nature, it is challenging to detect the existence of its noncollinear magnetization. Here, we show that a van der Waals junction based on a spin-spiral magnet and a quantum spin Hall insulator enables obtaining signatures of noncollinear magnetization directly from electrical measurements. Our strategy exploits the sensitivity of helical states to local breaking of time-reversal symmetry, potentially enabling the detection of local magnetic orders even in the absence of net magnetization. We show that the combination of spin-spiral order and nonmagnetic disorder gives rise to scattering in the helical channels that can be directly associated with the spiral exchange coupling and residual nonmagnetic disorder strength. Our results show how electrical transport measurement may offer a way to detect spin-spiral magnets by leveraging helical states in van der Waals heterostructures.