Strongly Correlated Transport in Topological Y-Junction Devices

TL;DR

This paper investigates electron transport in a topological Y-junction device with strong interactions, revealing a novel intermediate fixed point that alters conductance behavior compared to non-interacting models.

Contribution

It introduces a new analysis of strongly interacting helical edge states in a Y-junction, identifying an intermediate RG fixed point affecting transport properties.

Findings

Transport governed by an intermediate RG fixed point for strong repulsive interactions

Interactions qualitatively modify multiterminal topological device conductance

Extension of previous point-contact tunneling studies to Y-junctions

Abstract

I analyze electron transport through a Y-junction formed by helical edge states of a two-dimensional topological insulator (2DTI), focusing on the strongly interacting regime. An experimentally motivated device geometry and a spin-conserving tunneling Hamiltonian are proposed. I compute the conductance tensor and show that, for specific tunneling phases and strong repulsive interactions ($g<1/2$), transport is governed by an intermediate renormalization group fixed point that interpolates between the weak- and strong-tunneling limits. These results extend previous studies of point-contact tunneling and demonstrate how interactions qualitatively modify the transport properties of multiterminal topological devices.