Electronic Structure of Oxides at Interfaces

 

Tanusri Saha-Dasgupta

 

S.N.Bose National Centre for Basic Sciences, Kolkata, INDIA

tanusri@bose.res.in

 

 

The experimental advancement in layer-by-layer deposition technique has generated considerable attention in study of oxides at interfaces. In this talk, we will discuss the electronic structure of two such interfaces.

 

First, we will consider the one formed between a Mott insulator GdTiO3 (GTO) and a band insulator SrTiO3 (STO). [1] We compare  our results with those for the widely studied LaAlO3/SrTiO3 (LAO/STO) interface between two band insulators. GTO/STO was found to behave qualitatively different from that of LAO/STO. The microscopic origin of this difference will be discussed.

 

In the second example, we will discuss quantum wells formed by embedding the  double perovskite Ba2FeReO6 (BFRO), in the band insulator BaTiO3 (BTO).[2] we establish that the half-metallicity of bulk BFRO survives down to 1 nm thickness in BaTiO3/Ba2FeReO6/BaTiO3 heterostructures grown along the (001) and (111) directions. The mechanism of confinement driven by the suppressed hybridization between Re/Fe d states, which is distinct from the polar catastrophe, as operative in LAO/STO or GTO/STO, leads to an order of magnitude stronger confinement of the 2D electron gas. We further show low-energy bands of (111) heterostructure display nontrivial topological character.

 

[1] Hrishit Banerjee, Sumilan Banerjee, Mohit Randeria, Tanusri Saha -Dasgupta,

arXiv:1505.00339 (Scientific Report, 2015)

 

[2] Santu Baidya, Umesh V. Waghmare, Arun Paramekanti, and Tanusri Saha-Dasgupta Phys. Rev. B 92, 161106(R) (2015)