Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 3: Transport: Quantum Dots, Quantum Wires, Point Contacts

TT 3.4: Talk

Monday, March 20, 2017, 10:15–10:30, HSZ 201

Conductance through a helical state in an InSb nanowire — Jakob Kammhuber, Maja Cassidy, Adriaan Vuik, Michal Nowak, •Michael Wimmer, and Leo Kouwenhoven — QuTech and Kavli institute of nanoscience, TU Delft, Netherlands

The interplay of Rashba spin-orbit interaction and Zeeman splitting in nanowires gives rise to a so called "helical state", where carriers with opposite velocity have nearly opposite spins. In particular, this helical state should manifest itself in the quantum point contact (QPC) conductance as a dip in conductance from 2e²/h to 1e²/h.

Here, we discuss theoretically how such a helical state can be identified in QPC conductance by rotating the magnetic field. Using this technique, we have found experimental signatures consistent with a helical gap in InSb nanowires, and extracted a value for the spin-orbit coupling strength.