%0 Journal Article
%A Leis, Arthur
%A Rodenbücher, Christian
%A Szot, Krzysztof
%A Cherepanov, Vasily
%A Tautz, F. Stefan
%A Voigtländer, Bert
%T In-situ four-tip STM investigation of the transition from 2D to 3D charge transport in SrTiO3
%J Scientific reports
%V 9
%N 1
%@ 2045-2322
%C [London]
%I Macmillan Publishers Limited, part of Springer Nature
%M FZJ-2019-01643
%P 2476
%D 2019
%X The electrical properties of SrTiO3(100) single crystals were investigated in-situ at different stages of thermal reduction by means of a 4-tip STM. Using the tips of the STM as electrical probes, distance-dependent four-point measurements were performed at the surface of the crystal at room temperature after reduction by thermal treatment. For annealing temperatures T ≤ 700 °C, charge transport is confined to a surface region <3 μm below the surface. For reduction at T ≥ 900 °C a transition from a conducting 2D sheet with insulating bulk to a system with dominant 3D bulk conductivity is found. At an intermediate reduction temperature of T = 800 °C, a regime with mixed 2D/3D contributions is observed in the distance-dependent resistance measurements. Describing the depth-dependent conductivity with an analytical N-layer model, this regime of mixed 2D/3D conductivity is evaluated quantitatively under the assumption of an exponentially decaying conductivity profile, correlated with the previously observed depth-dependent dislocation density in the sample. A non-monotonous temperature dependence of the 3D conductivity in the respective conducting layer is found and possible underlying mechanisms are discussed, particularly with regard to non-intrinsic material properties depending on details of the sample preparation.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:30792428
%U <Go to ISI:>//WOS:000459281500045
%R 10.1038/s41598-019-38888-x
%U https://juser.fz-juelich.de/record/861059