Spin Transport in a Quantum Hall Insulator

Azaliya Azatovna Zagitova,Andrey Sergeevich Zhuravlev,Vladimir Umansky,Leonid Viktorovich Kulik

doi:10.3390/app11178131

Azaliya Azatovna Zagitova, Andrey Sergeevich Zhuravlev + Show 2 more

Open Access

https://doi.org/10.3390/app11178131

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Abstract

A novel experimental optical method, based on photoluminescence and photo-induced resonant reflection techniques, is used to investigate the spin transport over long distances in a new, recently discovered collective state—magnetofermionic condensate. The given Bose–Einstein condensate exists in a purely fermionic system (ν = 2 quantum Hall insulator) due to the presence of a non-equilibrium ensemble of spin-triplet magnetoexcitons—composite bosons. It is found that the condensate can spread over macroscopically long distances of approximately 200 μm. The propagation velocity of long-lived spin excitations is measured to be 25 m/s.

Highlights

The growing interest in spintronics [1,2] has been incited by the prospect of building fast, energy-efficient devices utilizing the electron spin
Due to optical transitions associated with the upper spin sublevel of the zero electron Landau level, the photo-induced resonant reflection (PRR) signal emerges as the filling factor is dropped to 1.4
By contrast, when it comes to the Hall insulator at the filling factor ν = 2, switching the laser diode on results in a PRR signal, implying the generation of a macroscopic number of non-equilibrium magnetoexcitons

Summary

Introduction

The growing interest in spintronics [1,2] has been incited by the prospect of building fast, energy-efficient devices utilizing the electron spin. There has been rapid development in magnonics [3], which uses spin waves to transport information [4,5]. Magnonic systems are free of many disadvantages of electronic systems associated with energy dissipation. An even more innovative idea for the spin transfer is to include vortex-like spin structures (skyrmions) into the spin dynamics. There have been reported experimental studies involving the manipulation of skyrmions, measuring their mass and velocity [8]. It is expected that dissipative spin transport can be realized in a skyrmion system. This paper investigates other promising candidates for spin transport similar to magnons, the long-lived spin excitations in a Hall insulator

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Conclusion