Christoph Brüne

TL;DR: The quantum phase transition at the critical thickness, d = 6.3 nanometers, was independently determined from the magnetic field–induced insulator-to-metal transition, providing experimental evidence of the quantum spin Hall effect.

TL;DR: In this article, the quantum spin Hall effect was observed in HgTe/(Hg,Cd)Te quantum wells with well width d 6.3 nanometers and the residual conductance was independent of sample width, indicating that it is caused by edge states.

TL;DR: The data confirm that the quantum transport through the (helical) edge channels is dissipationless and that the contacts lead to equilibration between the counterpropagating spin states at the edge, which agree quantitatively with the theory of the quantum spin Hall effect.

TL;DR: In this paper, a study using superconducting leads in contact with a quantum well reveals the presence of supercurrents along one-dimensional sample edges of a quantum spin Hall state.

TL;DR: The quantum spin Hall state is predicted to consist of two oppositely polarized spin currents travelling in opposite directions around the edges of a topological insulator as discussed by the authors, and non-local measurements of the transport in HgTe quantum wells confirm the polarized nature of these edge states.