Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 23: Quantum dots and wires: Transport properties I
HL 23.8: Vortrag
Dienstag, 26. Februar 2008, 12:45–13:00, EW 201
Local Density of States in Mesoscopic Samples from Scanning Gate Microscopy — •Marco G. Pala1, Benoit Hackens2, Frederico Martins3, Hermann Sellier3, Vincent Bayot2, Serge Huant3, and Thierry Ouisse3 — 1IMEP-LAHC-MINATEC, CNRS, INPG and UJF, BP 257, 38016 Grenoble, France — 2CERMIN, DICE Lab, UCL, B-1348 Louvain-la-Neuve, Belgium — 3Institut Néel, CNRS, and UJF, BP 166, 38042 Grenoble, France
We study the relationship between the local density of states (LDOS) and the conductance variation Δ G in scanning-gate-microscopy experiments on mesoscopic structures [1]. This is a weakly invasive technique, applicable to nanostructures patterned in subsurface two-dimensional (2D) electron gases. The probe is used as a scatterer which locally modifies the electron flow properties, and generates 2D conductance maps as a function of the tip position.
We present an analytical model showing the correspondence between the conductance shift Δ G and the LDOS in the single-channel transmission regime. We analyze the physical conditions for the validity of this relationship both for one-dimensional and two-dimensional systems when several channels contribute to the transport [2]. We focus on realistic Aharonov-Bohm rings including a random distribution of impurities and analyze the LDOS-Δ G correspondence by means of exact numerical simulations, when localized states or semi-classical orbits characterize the wavefunction of the system.
[1] F. Martins et al., Phys. Rev. Lett. 99, 136807 (2007)
[2] M.G. Pala et al., To be published.