Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 48: Poster 2
HL 48.28: Poster
Donnerstag, 26. März 2009, 15:00–17:30, P2
Tunable transverse rectification in density-modulated 2D-Systems: Ballistic of thermoelectric effect? — •Arkadius Ganczarczyk1, Christian Notthoff1, Martin Geller1, Axel Lorke1, Dirk Reuter2, and Andreas Wieck2 — 1Experimental Physics and CeNIDE, Universität Duisburg-Essen — 2Ruhr-Universität Bochum
We investigate tunable transverse rectification in a density-modulated two-dimensinal electron gas (2DEG) at low temperatures (4.2 K). The 2DEG is patterned into a long narrow conductive channel with source and drain contacts and a voltage probe on each side of the channel. Using gate electrodes we induce two stripes of different charge carrier density running parallel to the channel. The resulting density gradient perpendicular to the channel induces a transverse voltage, which - due to the symmetry of the device - does not change polarity when the current direction is reversed. We observe that the rectified transverse voltage increases with increasing density modulation and is proportional to 1/n1 - 1/n2, where n1 and n2 are the charge carrier densities in the two stripes. The observed transverse voltage can attributed to two different physical phenomena: Ballistic rectification and a thermoelectric effect. The results are discussed by using a billiard model, which describes the propagation of ballistic electrons in density-modulated 2D-systems. Furthermore, possible thermoelectric effects in the structure are discussed. Both models are compared in order to obtain a deeper insight into this novel rectification effect.