Seminár z fyziky tuhých látok - Richard Korytár (24.9.2019)

v utorok 24.9.2019 o 14:00 hod. v miestnosti F2/223

11. 09. 2019 11.16 hod.
Od: Richard Hlubina

Prednášajúci: Richard Korytár (Univerzita Karlova, Praha)

Názov: Quantum size-effects in atomic chains and molecular wires

Termín: 24.9.2019, 14:00 hod., F2/223

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)