Topological Physics – Phenomena in physics controlled by the topology (often: the homotopy theory) of the physical system.
General theory:
In electromagnetism:
A quantum spin Hall effect, is
a variant of the spin Hall effect where quantum effetcs play a role;
a variant of the quantum Hall effect where spin-orbit coupling in the underlying material (typically a topological insulator) takes the role of the external magnetic field.
The fact that no external field is needed in a quantum spin Hall effect make the materials that exhibit this effect (e.g. certain topological insulators) be attractive substrates for operating on the corresponding anyon-excitations. This makes the quantum spin Hall materials potential hardware for topological quantum computation.
The original proposal/prediction of a quantum spin Hall effect:
in graphene:
in topological insulators based on mercury telluride (“HgTe quantum wells”):
Andrei Bernevig, Shou-Cheng Zhang, Quantum Spin Hall Effect, Phys. Rev. Lett. 96, 106802 (2006) (arXiv:cond-mat/0504147, doi:10.1103/PhysRevLett.96.106802)
Andrei Bernevig, Taylor Hughes, Shou-Cheng Zhang, Quantum spin Hall effect and topological phase transition in HgTe quantum wells, Science 15 December 2006: 314, n. 5806, pp. 1757-1761 (doi:10.1126/science.1133734, arXiv:cond-mat/0611399)
Xiao-Gang Wen commented in Oct. 2013 (rev 2, rev 3): In fact, the above material have no quantum spin Hall effect since the spin is not conserved due to the spin-orbital interaction that makes the material non trivial, or the Quantum spin Hall effect defined in the paper is different from that defined in the Wiki: http://en.wikipedia.org/wiki/Quantum_spin_Hall_effect
Experimental detection:
Review:
Last revised on February 18, 2021 at 07:00:53. See the history of this page for a list of all contributions to it.