Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy

被引:36
作者
Schuetz, P. [1 ,2 ]
Christensen, D. V. [3 ]
Borisov, V. [4 ]
Pfaff, F. [1 ,2 ]
Scheiderer, P. [1 ,2 ]
Dudy, L. [1 ,2 ]
Zapf, M. [1 ,2 ]
Gabel, J. [1 ,2 ]
Chen, Y. Z. [3 ]
Pryds, N. [3 ]
Rogalev, V. A. [1 ,2 ,5 ]
Strocov, V. N. [5 ]
Schlueter, C. [6 ]
Lee, T. -L. [6 ]
Jeschke, H. O. [4 ]
Valenti, R. [4 ]
Sing, M. [1 ,2 ]
Claessen, R. [1 ,2 ]
机构
[1] Univ Wurzburg, Phys Inst, D-97074 Wurzburg, Germany
[2] Univ Wurzburg, Rontgen Ctr Complex Mat Syst RCCM, D-97074 Wurzburg, Germany
[3] Tech Univ Denmark, Dept Energy Convers & Storage, DK-4000 Roskilde, Denmark
[4] Goethe Univ Frankfurt Main, Inst Theoret Phys, D-60438 Frankfurt, Germany
[5] Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland
[6] Diamond Light Source, Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England
关键词
ELECTRON GASES; SURFACE; GAMMA; STATE;
D O I
10.1103/PhysRevB.96.161409
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The spinel/perovskite heterointerface gamma-Al2O3/SrTiO3 hosts a two-dimensional electron system (2DES) with electron mobilities exceeding those in its all-perovskite counterpart LaAlO3/SrTiO3 by more than an order of magnitude, despite the abundance of oxygen vacancies which act as electron donors as well as scattering sites. By means of resonant soft x-ray photoemission spectroscopy and ab initio calculations, we reveal the presence of a sharply localized type of oxygen vacancies at the very interface due to the local breaking of the perovskite symmetry. We explain the extraordinarily high mobilities by reduced scattering resulting from the preferential formation of interfacial oxygen vacancies and spatial separation of the resulting 2DES in deeper SrTiO3 layers. Our findings comply with transport studies and pave the way towards defect engineering at interfaces of oxides with different crystal structures.
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页数:6
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