Spin memory of the topological material under strong disorder

Inna Korzhovska (1) , Haiming Deng (1) , Lukas Zhao (1) , Yury Deshko (1) , Zhiyi Chen (1) , Marcin Konczykowski (2) , Shihua Zhao (1) , Simone Raoux (3) , Lia Krusin-Elbaum (1)

1 CCNY - City College of New York [CUNY]
2 LSI - Laboratoire des Solides Irradiés
3 HZB - Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Robustness to disorder is the defining property of any topological state. The ultimate disorder limits to topological protection are still unknown, although a number of theories predict that even in the amorphous state a quantized conductance might yet reemerge. Here we report that in strongly disordered thin films of the topological material Sb2Te3 disorder-induced spin correlations dominate transport of charge—they engender a spin memory phenomenon, generated by the nonequilibrium charge currents controlled by localized spins. We directly detect a glassy yet robust disorder-induced magnetic signal in films free of extrinsic magnetic dopants, which becomes null in a lower-disorder crystalline state. This is where large isotropic negative magnetoresistance (MR)—a hallmark of spin memory—crosses over to positive MR, first with only one e2/h quantum conduction channel, in a weakly antilocalized diffusive transport regime with a 2D scaling characteristic of the topological state. A fresh perspective revealed by our findings is that spin memory effect sets a disorder threshold to the protected topological state. It also points to new possibilities of tuning spin-dependent charge transport by disorder engineering of topological materials.

Domains: Superconductivity [cond-mat.supr-con]

Inna Korzhovska, Haiming Deng, Lukas Zhao, Yury Deshko, Zhiyi Chen, et al.. Spin memory of the topological material under strong disorder. Npj Quantum Materials, 2020, 5 (1), ⟨10.1038/s41535-020-0241-5⟩. ⟨hal-03069948⟩