Ultrafast spin-charge conversion at SnBi${}_2$Te${}_4$/Co topological insulator interfaces probed by terahertz emission spectroscopy

Abstract

Spin-to-charge conversion (SCC) involving topological surface states (TSS) is one of the most promising routes for highly efficient spintronic devices for terahertz (THz) emission. Here, the THz generation generally occurs mainly via SCC consisting in efficient dynamical spin injection into spin-locked TSS. In this work, we demonstrate sizable THz emission from a nanometric thick topological insultator (TI)/ferromagnetic junction - SnBi${}_2$Te${}_4$/Co - specifically designed to avoid bulk band crossing with the TSS at the Fermi level, unlike its parent material Bi${}_2$Te${}_3$. THz emission time domain spectroscopy (TDS) is used to indicate the TSS contribution to the SCC by investigating the TI thickness and angular dependence of the THz emission. This work illustrates THz emission TDS as a powerful tool alongside angular resolved photoemission spectroscopy (ARPES) methods to investigate the interfacial spintronic properties of TI/ferromagnet bilayers.

arXiv commentto appear in Advanced Optical materials (02/2022)

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Cited by in corpus (9)

• Spintronic Sources of Ultrashort Terahertz Electromagnetic Pulses
• Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers
• Maximizing the electromagnetic efficiency of spintronic terahertz emitters
• Excitation wavelength-dependent ultrafast THz emission from surface and bulk of three-dimensional topological insulators
• Inverse Rashba-Edelstein THz emission modulation induced by ferroelectricity in CoFeB/PtSe2/MoSe2//LiNbO3 systems
• Theory of spin and orbital charge conversion at the surface states of Bi_{1-x}Sb_x topological insulator
• Terahertz time-domain signatures of the inverse Edelstein effect in topological-insulator|ferromagnet heterostructures
• Spin and Orbital Rashba response in ferroelectric polarized PtSe${}_2$/MoSe${}_2$/LiNbO${}_3$ heterostructures
• Research on topological materials using ultrafast spectroscopy