Proposed Valley Valve from Four-Channel Valley Manipulation

Abstract

In $v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}y\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}s$, local maxima and minima in a semiconductor's electronic band structure are exploited for processing bits of information. Here a model of the $A\phantom{\rule{0}{0ex}}B$-stacked WS${}_{2}$/MoS${}_{2}$ bilayer heterostructure, in which inversion symmetry is designed to be ideal for Berry-curvature engineering, shows that four-bit valley manipulation can be achieved, going beyond the two-bit standard. This ingenious management leads to the proposal of a $v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}y$ $v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}v\phantom{\rule{0}{0ex}}e$, a device that realizes nonlocal resistances at multiple levels, being analogous to the spin valve of spintronics.