Dr. Suvankar Chakraverty

Associate Professor, Institute of Nano Science and Technology, INDIA

Title: KTaO3 – The new kid on the spintronics block

Schedule

Abstract:

In recent times, momentum dependent splitting of spin-bands in an electronic system, the “Rashba effect”, has gained a lot of interest because of its applications in future generation spintronic devices.[1,2] The Rashba effect is important not only because it has tremendous potential for technical applications, but also it is a hunting ground of emergent physical properties owing to the linear dispersion relation at the crossing point of the two spin bands.[3] In this work, we present observation of emergent phenomena arising at the interface of two insulating perovskite oxides due to Rashba spinband splitting. In our first work, we improvise a novel conducting interface by juxtaposing KTaO3 (KTO) with another insulator, namely LaVO3 (LVO).[4] This heterointerface exhibits strong spin-orbit coupling which is the highest among perovskite oxide heterostructures reported so far. The system is also found to show signature of topological chiral anomaly via observation planar Hall effect (PHE) and anomalous inplane magnetoresistance (AMR) similar to that observed for topological systems. [5] In our next work, we show the realization of conducting interface between ferromagnetic EuO and non-magnetic KTO. [6] This heterostructure is found to exhibit Shubnikov-de Haas oscillations. The observed oscillations suggest the presence of two Fermi surfaces. For both the Fermi surfaces, we have seen the presence of a non-trivial “Berry phase” suggesting that the surfaces enclose a “Dirac point” and the Berry phase originates from the inner and outer Fermi surfaces of the Rashba spin-split bands. Analysing the SdH, Hall and magnetoresistance data, we have drawn a possible band diagram near the Fermi surface for EuO-KTO heterointerface. Our observations suggest that perovskite oxides with strong spin orbit coupling and relativistic conduction electrons could be a hunting ground not only for spintronic materials but also for emergent physics.

Biography:

Designing (and understanding the physical properties) of new materials with integrated functionalities for spin-electronics (spintronics / skyrmionics) devices in the form of thin films and interfaces with atomic scale control and monitoring the growth process using laser molecular beam epitaxy method.

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