Interference phenomena in open quantum systems: applications for molecular switches and thermoelectric devices
DIPC Seminars
- Speaker
-
Daijiro Nozaki
- When
-
2016/06/09
14:00 - Place
- Donostia International Physics Center
- Add to calendar
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Interference phenomena in open quantum systems: applications for molecular
switches and thermoelectric devices
Daijiro Nozaki
Department of Theoretical Physics
University of Paderborn
Warburger Straße 100
33098 Paderborn, Nordrhein-westfalen, Germany
Quantum interference effects in molecular devices has drawn increasing
attention in the last decades because of unique features observed in
conductance spectrum applicable to thermoelectric devices and molecular
switches [1-3]. For the further development of single molecular devices
exploiting QI effects, it is of great theoretical and practical interest to
clarify the relationship between the line shape of conductance spectra
including QI features and controlling parameters such as electronic structures
(on-site energies and transfer integrals) and topologies of molecules.
In this talk, first I present a simple graphical method (parabolic diagram)
that we developed to visualize the relation between the electronic parameters
and line shape of conductance spectrum influenced by QI effect in the
molecular junction with a side group (T-shaped molecule) [4].
Next, we present systematic analysis of thermoelectric properties in a series
of molecular junctions having different topologies and QI features in toy
model basis [5].
We also shows recent result of switchable negative differential resistance (NDR) in porphyrine-based molecular devices [6]. Charge transport through a carbon-based molecular switch consisting of different tautomers of metal-free porphyrin embedded between graphene nanoribbons is studied by quilibrium Green's function formalism. Different low-energy and low-bias features are revealed, including NDR and antiresonances, both mediated by subtle quantum interference effects. Moreover, the molecular junctions can display moderate rectifying or nonlinear behavior depending on the position of the hydrogen atoms within the porphyrin core. We rationalize the mechanism leading to NDR and antiresonances by providing a detailed analysis of transmission pathways and frontier molecular orbital distribution.
References:
[1] S. V. Aradhya and L. Venkataraman, Nature Nanotechnol. 8, 399 (2013).
[2] W. Hong, H. Valkenier, G. Mészáros, D. Z. Manrique, A. Mishchenko, A.
Putz, P. M. García, C. J. Lambert, J. C. Hummelen, T. Wandlowski, Beilstein
J. Nanotechnol. 2, 699 (2011).
[3] C. M. Guédon, H. Valkenier, T. Markussen, K. S. Thygesen, J. C. Hummelen,
S. J. van der Molen, Nature Nanotechnol. 7, 305 (2012).
[4] DN, H. Sevinçli, S. M. Avdoshanko, R. Gutierrez, G. Cuniberti, PCCP 15,
13951 (2013).
[5] DN, S. M. Avdoshanko, H. Sevinçli, G. Cuniberti, J. Appl. Phys. 117,
074308 (2014).
[6] DN, Lokamani, A. Santana-Bonilla, A. Dianat, R. Gutierrez, G. Cuniberti,
J. Phys. Chem. Lett. 6, 3950 (2015).