Faculty of Mathematics, Physics
and Informatics
Comenius University in Bratislava

Condensed Matter Physics Seminar - Richard Korytár (24.9.2019)

Tuesday 24.9.2019 at 14:00, Lecture room F2/223

11. 09. 2019 11.25 hod.
By: Richard Hlubina

Richard Korytár (Univerzita Karlova, Praha):
Quantum size-effects in atomic chains and molecular wires

The ability to measure electronic conductance of single atoms and molecules is one of the most fascinating advances in physics and chemistry. In my talk I will consider short linear chains of single-atom or molecular devices, manifesting quantum size-effects. Theoretically, one of the simplest examples of a quantum size-effect is the particle-in-a-box problem. When a particle bounces off two potential wells, the energy spectrum is quantized and the gaps scale with the box’s length. I will demonstrate how this effect manifests itself in the conductance of linear oligoacenes, molecular chains whose basic unit is a benzene ring. Deeper understanding of quantum size-effects involves two limits: the infinite limit, represented by the band-structure, and the single unit (atom). For linear oligoacenes, I show that their specific band-structure implies unexpected incommensurate oscillations of the gap with length. In the second part of the talk I will consider chains of magnetic atoms, which display so called Kondo effect when adsorbed on the surface of a metal. Size effects in these chains offer a new perspective on the emergent heavy-fermion physics.

[1] M. Moro-Lagares, R. Korytár, M. Piantek, R. Robles, N. Lorente, J. Pascual, M. R. Ibarra and D. Serrate, Real space manifestations of coherent screening in atomic scale Kondo lattices, Nature Communications, 10:2211 (2019)
[2] T. Yelin, R. Korytár, N. Sukenik, R. Vardimon, B. Kumar, C. Nuckolls, F. Evers, O. Tal, Conductance saturation in highly conductive molecular junctions, Nature Materials, doi:10.1038/nmat4552 (2016)