Superluminal tachyon-like excitations of Dirac fermions in a topological insulator junction
1 Department of Physics and Astronomy, Georgia State University - Atlanta, GA 30303, USA
2 Department of Physics and Astronomy, University of Manitoba - Winnipeg, Canada R3T 2N2
Received: 10 September 2012
Accepted: 11 September 2012
We have considered a system of two topological insulators and have determined the properties of the surface states at the junction. Here we report that these states, under certain conditions exhibit superluminous (tachyonic) dispersion of the Dirac fermions. Although superluminal excitations are known to exist in optical systems, this is the first demonstration of possible tachyonic excitations in a purely electronic system. The first ever signature of tachyons could therefore be found experimentally in a topological insulator junction.
PACS: 73.20.-r – Electron states at surfaces and interfaces / 73.43.-f – Quantum Hall effects / 03.30.+p – Special relativity
© EPLA, 2012