Delafossite oxides: natural, ultra-pure metal-insulator heterostructures

by Dr Veronika Sunko (Max Planck Institute for Chemical Physics of Solids, Dresden)

Monday 1 Jun 2020, 16:00 → 17:00 Asia/Shanghai

ONLINE

Abstract

Delafossite oxides are layered compounds, which can be thought of as natural hetero-structures of triangularly coordinated metallic sheets and transition metal oxide blocks. A fascinating range of electronic states can be found both in their bulk and on their surfaces, including extremely high conductivity^1,2  in PtCoO₂ and PdCoO₂, maximal Rashba-like spin-splitting³ on the transition metal terminated surfaces of PtCoO₂, PdCoO₂ and PdRhO₂, Stoner ferromagnetism⁴ on the Pd-terminated surface of PdCoO₂ and, perhaps most remarkably, an intertwined spin-charge response due to a Kondo coupling between metallic and Mott insulating layers⁵ in PdCrO₂. Our group has investigated these states experimentally with transport measurements and angle resolved photoe­­mission, and theoretically with first principles calculations and model Hamiltonians, where applicable. I will show how in a number of cases the simplicity and cleanliness of the materials allows us to pinpoint to the underlying cause for the remarkable electronic behavior, and in turn to use delafossites as model systems to understand complex phenomena.

 

1. Kushwaha, P., Sunko, V., Moll, P.J.W., Bawden, L., Riley, J.M., Nandi, N., Rosner, H., Schmidt, M.P.,Arnold, F., Hassinger, E., Kim, T.K., Hoesch, M., Mackenzie, A.P., King, P.D.C., 2015, Science Advances 1, e1500692.
2. Sunko, V., McGuinness, P.J., Chang, C. S., Zhakina, E., Khim, S., Dreyer, C. E., Konczykowski, M., Borrmann, H., Moll, P. J. W., Konig, M., Muller, D.A., Mackenzie. A. P., 2020 Physical Review X, 10(2):021018.
3. Sunko, V., Rosner, H., Kushwaha, P., Khim, S., Mazzola, F., Bawden, L., Clark, O.J., Riley, J.M., Kasinathan, D., Haverkort, M.W., Kim, T.K., Hoesch, M., Fujii, J., Vobornik, I., Mackenzie, A.P., King, P.D.C., 2017, Nature 549, 492
4. Mazzola, F., Sunko, V., Khim, S., Rosner, H., Kushwaha, P., Clark, O.J., Bawden, L., Marković, I., Kim, T.K., Hoesch, M., Mackenzie, A.P., King, P.D.C., 2017., PNAS 51, 12956
5. Sunko, V., Mazzola, F., Kitamura, S., Khim, S., Kushwaha, P., Clark, O. J., Watson, M., Marković, I., Biswas, D., Pourovskii, L., Kim, T. K., Lee, T.-L. , Thakur, P. K., Rosner, H., Georges, A., Moessner, R., Oka, T., Mackenzie, A. P., and King, P. D. C., 2020, Science Advances 6, eaaz0611

Biography

2019 PhD at University of St Andrews, UK (supervisors: Prof. Phil King and Prof. Andy Mackenzie)

2019-Present Postdoc at Max Planck Institute for Chemical Physics of Solids, Dresden, Germany (collaborator: Andy Mackenzie)

2020-2023 Miller Postdoctoral Fellow at UC Berkeley (host: Prof. Joseph Orenstein)

 

Prizes & awards: Spring Thesis Prize (2019), Richard L. Greene Dissertation Award in Experimental Condensed Matter of Materials Physics (2020), Otto Hahn Medal of the Max Planck Society (2020), Miller Fellowship (2020-2023)

 

Research Topics: Delafossites, strongly correlated electron materials under uniaxial strain, angle-resolved photoemission spectroscopy

Division

Condensed Matter

Other information

Venue: TDLI Meeting Room 200

Here is the Zoom link if you prefer to join us remotely:

Meeting room: https://cernet.zoom.com.cn/j/68086437071