Two-Dimensional Photogalvanic Spin-Battery

Abstract

Pure spin current is of central importance in spintronics, and typically a sizable spin-orbit coupling (SOC) is needed to generate it. This study proposes using the photogalvanic effect occurring in a two-dimensional material (here phosphorene) $w\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}h\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}t$ $S\phantom{\rule{0}{0ex}}O\phantom{\rule{0}{0ex}}C$ to deliver pure spin current to the outside world at zero bias voltage, with no accompanying charge current. This ``spin battery'' system harvests photons for its energy source, and thus presents an innovative approach to self-powered flexible spintronics, including wearable devices.