Dynamic Nuclear Spin Polarization Induced by the Edelstein Effect at Bi(111) Surfaces

Abstract

Nuclear spin polarization induced by hyperfine interaction and the Edelstein effect due to strong spin-orbit interaction is investigated by quantum transport in Bi(111) thin film samples. The Bi(111) films are deposited on mica by van der Waals epitaxial growth. The Bi(111) films show micrometer-sized triangular islands with 0.39 nm step height, corresponding to the Bi(111) bilayer height. At low temperatures a high current density is applied for fixed durations to generate a non-equilibrium carrier spin polarization by the Edelstein effect at the Bi(111) surface, which then induces dynamic nuclear polarization by hyperfine interaction. Comparative quantum magnetotransport antilocalization measurements show that the quantum phase decoherence times decrease and the spin-orbit decoherence times increase as the polarization duration increases. Both outcomes indicate the suppression of antilocalization by the in-plane Overhauser field from the nuclear polarization and allow a quantification of the Overhauser field. Hence nuclear polarization was both achieved and quantified by a purely electronic transport-based approach.

Spin–orbit torque on nuclear spins exerted by a spin accumulation via hyperfine interactions

“…1. Figure 4 also shows functions ( ) f con 1 and ( ) f con 2 , given by equations ( 6) and (7). The nonequilibrium part of the Fermi contact and dipolar magnetization, rules by ( ) f con 2 and…”

“…Several methods have been developed to overcome this limitation via generating a dynamic nuclear spin polarization, which can significantly improve the detection limit and resolution of NMR spectroscopy [2]. These methods include optical [3] and electrical techniques [4][5][6][7], and are particularly useful for studying low-dimensional materials, where the number of nuclei is too low for conventional NMR techniques to work [8]. The ongoing developments of new techniques for inducing nonequilibrium nuclear spin polarization, along with new detection schemes, are crucial for advancing the capabilities of NMR spectroscopy and expanding its potential applications [9].…”