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arXiv · 1912.07166

Engineered spin-orbit interactions in LaAlO$_3$/SrTiO$_3$-based 1D serpentine electron waveguides

Megan Briggeman·Jianan Li·Mengchen Huang·Hyungwoo Lee·Jung-Woo Lee·Kitae Eom·Chang-Beom Eom·Patrick Irvin·Jeremy Levy
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Abstract

The quest to understand, design, and synthesize new forms of quantum matter guides much of contemporary research in condensed matter physics. One-dimensional (1D) electronic systems form the basis for some of the most interesting and exotic phases of quantum matter. The variety of experimentally-accessible ballistic 1D electronic systems is highly restricted, and furthermore these systems typically have few tuning parameters other than electric and magnetic fields. However, electron waveguides formed from two-dimensional (2D) LaAlO$_3$/SrTiO$_3$ heterointerfaces exhibit remarkable 1D properties, including ballistic multi-mode transport and strong attractive electron-electron interaction, but these systems conspicuously lack strong or tunable spin-orbit interactions. Here we describe a new class of quasi-1D nanostructures, based on LaAlO$_3$/SrTiO$_3$ electron waveguides, in which a sinusoidal transverse spatial modulation is imposed. Nanowires created with this "serpentine" modulation display unique dispersive features in the subband spectra, namely (1) a significant shift ($\sim$ 7 tesla) in the spin-dependent subband minima, and (2) fractional conductance plateaus, some of which are continuously tunable with a magnetic field. The first property can be understood as an engineered spin-orbit interaction associated with the periodic acceleration of electrons as they undulate through the nanowire (ballistically), while the second property signifies the presence of enhanced electron-electron scattering in this system due to the imposed periodic structure. The ability to engineer these interactions in quantum wires contributes to the tool set of a 1D solid-state quantum simulation platform.

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Megan Briggeman, Jianan Li, Mengchen Huang, Hyungwoo Lee, Jung-Woo Lee, Kitae Eom, Chang-Beom Eom, Patrick Irvin, Jeremy Levy. 2019-12-16. Engineered spin-orbit interactions in LaAlO$_3$/SrTiO$_3$-based 1D serpentine electron waveguides. https://doi.org/10.1126/sciadv.aba6337

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