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arXiv · 2407.03120

Theory of spin and orbital charge conversion at the surface states of Bi_{1-x}Sb_x topological insulator

Armando Pezo·Jean-Marie George·Henri Jaffrès
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Abstract

Topological insulators are quantum materials involving Time-reversal protected surface states(TSS) making them appealing candidates for the design of next generation of highly efficient spintronic devices. The very recent observation of large transient spin-charge conversion (SCC) and subsequent powerful THz emission from Co|Bi_{1-x}Sb_x bilayers clearly demonstrates such potentiality and feasibility for the near future. Amongst the exotic properties appearing in and at the surface of such quantum materials, spin-momentum locking (SML) and Rashba-Edelstein effects remain as key ingredients to effectively convert the spin degree of freedom into a charge or a voltage signal. In this work, we extend our analyses to the quantification of orbital momentum-locking and related orbital charge conversion effects in Bi_{0.85}Sb_{0.15} via orbital Rashba-Edelstein effects. In that sense, we will provide some clear theoretical and numerical insights implemented by multi-orbital and multi-layered tight-binding methods (TB) to clarify our recent experimental results obtained by THz-TDS spectroscopy.

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Armando Pezo, Jean-Marie George, Henri Jaffrès. 2024-07-03. Theory of spin and orbital charge conversion at the surface states of Bi_{1-x}Sb_x topological insulator. https://doi.org/10.1103/physrevresearch.6.043332

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