Strong electron-electron interactions of a Tomonaga-Luttinger liquid observed in InAs quantum wires

Abstract

We report strong electron-electron interactions in quantum wires etched from an InAs quantum well, a material known to have strong spin-orbit interactions. We find that the current through the wires as a function of the bias voltage and temperature follows the universal scaling behavior of a Tomonaga-Luttinger liquid. Using a universal scaling formula, we extract the interaction parameter and find strong electron-electron interactions, increasing as the wires become more depleted. We establish theoretically that spin-orbit interactions cause only minor modifications of the interaction parameter in this regime, indicating that genuinely strong electron-electron interactions are indeed achieved in the device. Our results suggest that etched InAs wires provide a platform with both strong electron-electron and strong spin-orbit interactions. * sato@meso.t.u-tokyo.ac.jp; Contributed equally to this work † matsuo@ap.t.u-tokyo.ac.jp; Contributed equally to this work

Charge transport of a spin-orbit-coupled Luttinger liquid

“…For parameters relevant to Ref. [40], we obtain δv/v F 0.1 in the strong-interaction regime (that is, close to the bottom of the lowest subband).…”

“…For parameters of Ref. [40], the small value of δv/v F 0.1 leads to negligible changes ∆α bulk . We include also larger values of δv/v F , which are relevant for nanowires with weaker transverse confinement or stronger spin-orbit coupling.…”

“…Recently, Ref. [40] attempted to determine the interaction strength in nanowires made of InAs. There, it was found that the current-bias curves fit well to the universal scaling formula of a Luttinger liquid [16,41] for charge density spanning an appreciable range.…”

“…In a nutshell, in Ref. [40], we used the formulas for wires with zero spin-orbit coupling. Here, we provide the theory for wires with arbitrary spin-orbit coupling strength.…”

Crossed Andreev reflection in InSb flake Josephson junctions

“…2(b), which is in range of what one can expect for a combination of a small coupling to the contact, while maintaining the Fermi velocity in the edges [6,21]. Additionally, electron-electron interaction in the 1D edges could also reduces the direct Andreev reflection and lead to a large f [35]. The the large offset f and h/e periodicity mean that the CAR amplitude exceeds the direct Andreev reflection, an interesting topic and regime for future experiments.…”