TY  - JOUR
AU  - Leis, Arthur
AU  - Rodenbücher, Christian
AU  - Szot, Krzysztof
AU  - Cherepanov, Vasily
AU  - Tautz, F. Stefan
AU  - Voigtländer, Bert
TI  - In-situ four-tip STM investigation of the transition from 2D to 3D charge transport in SrTiO3
JO  - Scientific reports
VL  - 9
IS  - 1
SN  - 2045-2322
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - FZJ-2019-01643
SP  - 2476
PY  - 2019
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - pmid:30792428
UR  - <Go to ISI:>//WOS:000459281500045
DO  - DOI:10.1038/s41598-019-38888-x
UR  - https://juser.fz-juelich.de/record/861059
ER  -