Large-Area Intercalated Two-Dimensional Pb/Graphene Heterostructure as a Platform for Generating Spin-Orbit Torque.

Vera, Alexander; Zheng, Boyang; Yanez, Wilson; Yang, Kaijie; Kim, Seong Yeoul; Wang, Xinglu; Kotsakidis, Jimmy C; El-Sherif, Hesham et al. · ACS Nano · 2024

basic_science · Level V

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Abstract

A scalable platform to synthesize ultrathin heavy metals may enable high-efficiency charge-to-spin conversion for next-generation spintronics. Here, we report the synthesis of air-stable, epitaxially registered monolayer Pb underneath graphene on SiC (0001) by confinement heteroepitaxy (CHet). Diffraction, spectroscopy, and microscopy reveal that CHet-based Pb intercalation predominantly exhibits a mottled hexagonal superstructure due to an ordered network of Frenkel-Kontorova-like domain walls. The system's air stability enables <i>ex situ</i> spin torque ferromagnetic resonance (ST-FMR) measurements that demonstrate charge-to-spin conversion in graphene/Pb/ferromagnet heterostructures with a 1.5× increase in the effective field ratio compared to control samples.