Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Topological Insulators 4 (jointly with DS, HL, MA, and O)

MA 41.6: Talk

Thursday, March 14, 2013, 16:45–17:00, H18

Quasi-ballistic transport of Dirac fermions in a Bi₂Se₃ nanowire — •Joseph Dufouleur¹, Louis Veyrat¹, Andreas Teichgräber¹, Stephan Neuhaus¹, Christian Nowka¹, Silke Hampel¹, J érôme Cayssol^2,3, Joachim Schumann¹, Barbara Eichler¹, Oliver Schmidt¹, Bernd Büchner¹, and Romain Giraud^1,4 — ¹Leibniz Institute for Solid State and Materials Research, IFW Dresden, 01171 Dresden, Germany — ²LOMA, University Bordeaux 1, F-33045 Talence, France — ³Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany — ⁴CNRS - Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France

Quantum coherent transport of Dirac fermions in a mesoscopic nanowire of the 3D topological insulator Bi₂Se₃ is studied in the weak-disorder limit. At very low temperatures, many harmonics are evidenced in the Fourier transform of Aharonov-Bohm oscillations, revealing the long phase-coherence length of surface states. Remarkably, from their exponential temperature dependence, we infer an unusual 1/T power law for the phase coherence length L_ϕ(T). This decoherence is typical for quasi-ballistic fermions weakly coupled to the dynamics of their environment.