Local probing of coupled interfaces between two-dimensional electron and hole gases in oxide heterostructures by variable-temperature scanning tunneling spectroscopy

Huijben, M. and Kockmann, D. and Huijben, J. and Kleibeuker, J.E. and Houselt van, A. and Koster, G. and Blank, D.H.A. and Hilgenkamp, H. and Rijnders, G. and Brinkman, A. and Zandvliet, H.J.W. (2012) Local probing of coupled interfaces between two-dimensional electron and hole gases in oxide heterostructures by variable-temperature scanning tunneling spectroscopy. Physical review B: Condensed matter and materials physics, 86 (3). 035140 - . ISSN 1098-0121

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Abstract:	The electronic structure of an epitaxial oxide heterostructure containing two spatially separated two-dimensional conducting sheets, one electronlike (2DEG) and the other holelike (2DHG), has been investigated using variable temperature scanning tunneling spectroscopy. Heterostructures of LaAlO3/SrTiO3 bilayers on (001)-oriented SrTiO3 (STO) substrates provide the unique possibility to study the coupling between subnanometer spaced conducting interfaces. The band gap increases dramatically at low temperatures due to a blocking of the transition from the conduction band of the STO substrate to the top of the valence band of the STO capping layer. This prevents the replenishment of the depleted electrons in the capping layer from the underlying 2DEG and enables charging of the 2DHG by applying a negative sample bias voltage within the band gap region. At low temperatures the 2DHG can be probed separately with the proposed experimental geometry, although the 2DEG is located less than 1 nm below
Item Type:	Article
Copyright:	© American Physical Society
Faculty:	Science and Technology (TNW)
Research Chair:	Nano Electronic Materials (NEM)
Research Group:	Inorganic Materials Science (IMS) Physics of Interfaces and Nanomaterials (PIN) Interfaces and Correlated Electron Systems (ICE) Catalytic Processes and Materials (CPM)
Link to this item:	http://purl.utwente.nl/publications/81171
Official URL:	http://dx.doi.org/10.1103/PhysRevB.86.035140
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