[Joint Seminar] Universal transport features in spin-orbit-coupled quantum wires


Tuesday, October 12, 2021 - 09:00 to 10:00




Joint seminar with Quantum Machines Unit (Prof. Jason Twamley)


Dr. Chen-Hsuan Hsu
RIKEN Center for Emergent Matter Science, Japan


Universal transport features in spin-orbit-coupled quantum wires


Quantum wires made of materials with strong spin-orbit coupling have recently drawn significant attention, owing to their potential in stabilizing topological states of matter. In this talk, I will present our recent works on the transport properties of a quasi-one- dimensional spin-orbit-coupled quantum wire. First, I will discuss the spin-orbit-induced band distortion of a wire in the one-transverse-subband regime and its effects on the current-bias curve in the presence of various types of impurities. The findings can be summarized in the form of the universal scaling curve with an exponent depending on the impurity type, the electron-electron interaction strength and the spin-orbit-induced band distortion [1]. The results can serve as guidance for quantifying the interaction strength of spin-orbit-coupled wires through transport measurements [2], which is crucial for identifying a promising platform for topological phases [3]. In the second part of my presentation, I consider a quantum wire in which the lowest two transverse subbands are populated. In the presence of the Coulomb interaction and a helical field (arising from either intrinsic or extrinsic spin-orbit coupling), novel backscattering processes result in scattering resonances and partial gaps, giving rise to non-standard plateaus and conductance dips at certain electron densities [4]. The positions and values of these dips are independent of material parameters, serving as direct transport signatures of this mechanism. Observation of the universal conductance dips would identify a strongly correlated system hosting fractional excitations, resembling the fractional quantum Hall states.

[1] CHH, Stano, Sato, Matsuo, Tarucha, and Loss, Phys. Rev. B 100, 195423 (2019).
[2] Sato, Matsuo, CHH, Stano, Ueda, Takeshige, Kamata, Lee, Shojaei, Wickramasinghe,
Shabani, Palmstrøm, Tokura, Loss, and Tarucha, Phys. Rev. B 99, 155304 (2019).
[3] CHH, Stano, Klinovaja, and Loss, topical review on helical liquids in semiconductors, to appear in Semicond. Sci. Technol. (2021), DOI: 10.1088/1361-6641/ac2c27. Preprint:
[4] CHH, Ronetti, Stano, Klinovaja, and Loss, Phys. Rev. Research 2, 043208 (2020).


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