Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 41: Transport: Graphene (organized by TT)
HL 41.5: Vortrag
Dienstag, 1. April 2014, 10:45–11:00, WIL C107
Ballistic transport in graphene nanoconstrictions — •Danny J. M. Jörger1,2, Bernat Terrés1,2, Stephan Engels1,2, Kenji Watanabe3, Takashi Taniguchi3, Slava V. Rotkin1,4, and Christoph Stampfer1,2 — 1JARA-FIT and II. Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany — 2Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany — 3National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan — 4Physics Department, Lehigh University, Bethlehem, Pennsylvania 18015, USA
Graphene nanodevices, such as for example nanoconstrictions are interesting systems for studying mesoscopic phenomena. Recent developments in the fabrication of graphene devices have revealed a significant increase in carrier mobility (e.g. 200.000 cm2/Vs in bulk samples), making mean free path in the order of device dimensions accesible. This allows to investigate quantum interference effects and ballistic transport in nanostructured graphene. We discuss the differences in electrostatic coupling (α ≈ 9.4× 1010 cm−2V−1) at high and low magnetic fields and the width-dependency of the overall conductance level at zero magentic field. Results confirm the Dirac fermion nature of confined charge carriers in graphene. We report on the observation of quasi one-dimensional subband transport characteristics in graphene nanoconstrictions encapsulated in hexagonal boron nitride. The ballistic nature of the transport in our devices (lm ≥ 500 nm) allows to study the interplay between confinement and Landau quantization and its crossover.