Universality of electron mobility in LaAlO3/SrTiO3 and bulk SrTiO3

Autor: B. I. Shklovskii, Dennis Christensen, Yunzhong Chen, K. V. Reich, Harry L. Tuller, Felix Trier, Yuze Zhang, Nini Pryds
Rok vydání: 2017
Předmět:
Zdroj: Trier, F, Reich, K V, Christensen, D V, Zhang, Y, Tuller, H L, Chen, Y, Shklovskii, B I & Pryds, N 2017, ' Universality of electron mobility in LaAlO 3 /SrTiO 3 and bulk SrTiO 3 ', Applied Physics Letters, vol. 111, no. 9, 092106 . https://doi.org/10.1063/1.5001316
arXiv
ISSN: 1077-3118
0003-6951
Popis: Metallic LaAlO$_3$/SrTiO$_3$ (LAO/STO) interfaces attract enormous attention, but the relationship between the electron mobility and the sheet electron density, $n_s$, is poorly understood. Here we derive a simple expression for the three-dimensional electron density near the interface, $n_{3D}$, as a function of $n_s$ and find that the mobility for LAO/STO-based interfaces depends on $n_{3D}$ in the same way as it does for bulk doped STO. It is known that undoped bulk STO is strongly compensated with $N \simeq 5 \times 10^{18}~\rm{cm^{-3}}$ background donors and acceptors. In intentionally doped bulk STO with a concentration of electrons $n_{3D} < N$ background impurities determine the electron scattering. Thus, when $n_{3D} < N$ it is natural to see in LAO/STO the same mobility as in the bulk. On the other hand, in the bulk samples with $n_{3D} > N$ the mobility collapses because scattering happens on $n_{3D}$ intentionally introduced donors. For LAO/STO the polar catastrophe which provides electrons is not supposed to provide equal number of random donors and thus the mobility should be larger. The fact that the mobility is still the same implies that for the LAO/STO the polar catastrophe model should be revisited.
4 pages and 1 figure
Databáze: OpenAIRE
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