Condensed Matter Physics Seminar - Richard Korytár (24.9.2019)
Tuesday 24.9.2019 at 14:00, Lecture room F2/223
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.
 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)
 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)