Realization of a Valley Superlattice

Abstract

In a number of widely-studied materials, such as Si, AlAs, Bi, graphene, MoS2, and many transition metal dichalcogenide monolayers, electrons acquire an additional, spin-like degree of freedom at the degenerate conduction band minima, also known as "valleys". External symmetry breaking fields such as mechanical strain, or electric or magnetic fields, can tune the valley-polarization of these materials making them suitable candidates for "valleytronics". Here we study a quantum well of AlAs, where the two-dimensional electrons reside in two energetically degenerate valleys. By fabricating a strain-inducing grating on the sample surface, we engineer a spatial modulation of the electron population in different valleys, i.e., a "valley superlattice" in the quantum well plane. Our results establish a novel manipulation technique of the valley degree of freedom, paving the way to realizing a valley-selective layered structure in multi-valley materials, with potential application in valleytronics.

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Cited by in corpus (5)

• Dirac wave transmission in Lévy disordered systems
• Electronic transport in disordered graphene superlattices with scale-free correlated barrier spacements
• In-situ tunable giant electrical anisotropy in a grating gated AlGaN/GaN two-dimensional electron gas
• Emergent flat band lattices in spatially periodic magnetic fields
• Valley Gapless Semiconductor: Models and Applications