Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.51: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Resistivity and Hall-Effect Measurements on LaAlO3/SrTiO3−δ Heterostructures — •Ahmed Sleem1,2, Dirk Fuchs1, Philipp Müller3, Rudolf Schneider1, Dagmar Gerthsen3, and Hilbert von Löhneysen1,4 — 1Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany — 2Fakultät für Physik, Karlsruher Institut für Technologie, 76031 Karlsruhe, Germany — 3Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie, 76031 Karlsruhe, Germany — 4Physikalisches Institut, Karlsruher Institut für Technologie, 76031 Karlsruhe, Germany
The influence of the oxygen partial pressure p(O2) during film deposition on the transport properties of LaAlO3/SrTiO3−δ heterostructures was analyzed by resistivity and Hall-effect measurements. To this end, thin films of LaAlO3 were grown epitaxially by pulsed laser deposition on TiO2 terminated <001> oriented SrTiO3 substrates at different oxygen partial pressure p(O2), i. e., 10−3 mbar ≥ p(O2) ≥ 10−5 mbar. Electrical contacts to the interface were prepared by argon ion-etching and subsequent filling by sputtering of Pt pads. Resistivity measurements were carried out in Van-der-Pauw geometry for 4.2 K ≤ T ≤ 300 K. The charge carrier concentration, ne, and mobility, µe, were deduced from the Hall-constant, RH, and conductivity, σ , at room temperature and 4.2K. With decreasing p(O2) the resistivity changes from an insulating/semi-conductive to a metallic behavior. Experimental results with respect to the sheet resistance RS, ne, and µe versus p(O2) will be presented and discussed.