Efficient Spin‐to‐Charge Interconversion in Weyl Semimetal TaP at Room Temperature

Abstract

In this paper, spin‐to‐charge current conversion properties in the Weyl semimetal TaP by means of the inverse Rashba–Edelstein effect (IREE) with the interfacial integration of this quantum material with the ferromagnetic metal Permalloy (Py = Ni81Fe19) are presented. The spin currents are generated in the Py layer by the spin pumping effect (SPE) from microwave‐driven ferromagnetic resonance and are detected by a dc voltage along the TaP crystal, at room temperature. A field‐symmetric voltage signal is observed without the contamination of asymmetrical lines due to spin rectification effects observed in studies using metallic ferromagnets. The observed voltage is attributed to spin‐to‐charge current conversion based on the IREE, made possible by the spin–orbit coupling induced intrinsically by the bulk band structure of Weyl semimetals. The measured IREE coefficient λIREE = (0.30 ± 0.01) nm is two orders of magnitude larger than in graphene and is comparable to or larger than the values reported for some metallic interfaces and for several topological insulators.

Probing the Spin-Momentum Locking on Rashba Surfaces via Spin Current

“…The direct and inverse Rashba–Edelstein effects have been explored in different systems such as graphene, transition metal dichalcogenides (TMDs), LaAlO 3 /SrTiO 3 , Bi/Ag and nGaAs/InGaAsP interfaces, and in topological insulators. − Among materials with surface states, antimony (Sb) has proven to be a unique material. Sb is not only an elemental material but also a constituent element of several topological materials, and it can be a topological insulator by itself. , Furthermore, a recent study showed that Sb films can be grown by sputtering without the need of heat treatment or the use of special substrates and still present surface states .…”