Strain-induced indirect-to-direct bandgap transition in an np-type LaAlO3/SrTiO3(110) superlattice

文献情報

出版日 2019-03-08

DOI 10.1039/C8CP07761D

インパクトファクター 3.676

著者

L. Wang, W. Pan, W. X. Hu, D. Y. Sun

原文を見る

要旨

Using first-principles calculations, we studied the influence of in-plane strain on the electronic properties of the polar LaAlO3/SrTiO3 (LAO/STO)(110) superlattice. We propose that alternate positively (n-type) and negatively (p-type) charged interfaces can be introduced along the [110] direction, without changing the stoichiometry of the system, if the np-type LAO/STO(001) superlattice is constructed in a 45° stepped pattern. We find that when the LAO–STO layer thickness is larger than the critical thickness of the insulator–metal transition, a quasi-two dimensional hole gas and an anisotropic quasi-two dimensional electron gas are formed at alternate interfaces. By applying uniaxial in-plane strains, an unexpected indirect-to-direct bandgap transition occurs in the polar LAO/STO(110) superlattices. The strain-induced changes in the O-2p orbitals near the p-type interface modify the dispersion of valence-band edges, leading to the transition.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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