Hard x-ray photoemission and density functional theory study of the internal electric field in SrTiO3/LaAlO3 oxide heterostructures

Physical Review B - Condensed Matter and Materials Physics

Volumn 87, Issue 8, 2013, Pages

  Slooten, E ^a   Zhong, Zhicheng ^b   Molegraaf, H J A ^b   Eerkes, P D ^b   De Jong, S ^a   Massee, F ^a   Van Heumen, E ^a   Kruize, M K ^b   Wenderich, S ^b   Kleibeuker, J E ^b   Gorgoi, M ^c   Hilgenkamp, H ^b   Brinkman, A ^b   Huijben, M ^b   Rijnders, G ^b   Blank, D H A ^b   Koster, G ^b   Kelly, P J ^b   Golden, M S ^a  

^a UNIVERSITY OF AMSTERDAM   (Netherlands)

^b UNIVERSITY OF TWENTE   (Netherlands)

^c HAHN MEITNER INSTITUT   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84874540609     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.87.085128     Document Type: Article

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47. Seeing as in the 25 % oxygen-deficient case the DFT data predict the system to be metallic right from the outset, the change from a minor downward shift to a clear movement to higher La 5 s binding energy at n > 4 in Fig. is not linked to the onset of metallicity at n = 4 observed in transport experiments. The fact that the yellow shaded areas in Fig. shift to the left as n increases illustrates more La 5 s levels with a higher BE than is the case for the calculation for n = 1, and it is also evident that this proportion increases rapidly for n > 4. We speculate that one possible cause of this could be an interaction or coupling between holes in the outermost, oxygen-deficient surface and electrons at the STO/LAO interface. This interaction could be such that beyond a certain LAO thickness (here n ∼ 4) the energetics within the LAO nearer the STO substrate changes, resulting in the acceleration in the downward trend seen in the green points of Fig. for n > 4.