Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 52: Quantum Impurities and Kondo Physics
TT 52.2: Talk
Thursday, April 4, 2019, 09:45–10:00, H7
Conventional and ferromagnetic Kondo regimes in frustrated quantum dot trimers coupled to ferromagnetic lead — •Krzysztof Wójcik1 and Ireneusz Weymann2 — 1Institute of Molecular Physics, Polish Academy of Sciences, 60-179 Poznań, Poland — 2Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań, Poland
Quantum dot trimers coupled to the metallic lead through one of the quantum dots are known to exhibit the quantum phase transition between the conventional anti-ferromagnetic Kondo regime and the ferromagnetic Kondo regime [1,2]. For geometrically symmetric case, the transition is protected by the symmetry arising from frustration in the nanostructure and has a level-crossing nature. On the contrary, for asymmetric trimers the level crossing may be avoided and the transition becomes of Kosterlitz-Thoules type [2,3]. In our contribution we examine the fate of this transition in the presence of ferromagnetic lead. We show that in the particle-hole symmetry (PHS) case the results remain qualitatively the same as in the non-magnetic case, and focus on presenting the consequences of the exchange field arising in the frustrated nanostructure outside the PHS point.
[1] A. K. Mitchell, T. F. Jarrold, D. E. Logan, Phys. Rev. B 79, 085124 (2009).
[2] A. K. Mitchell, T. F. Jarrold, M. R. Galpin, D. E. Logan, J. Phys. Chem. B 117, 12777 (2013).
[3] P. P. Baruselli, R. Requist, M. Fabrizio, E. Tosatti, Phys. Rev. Lett. 111, 047201 (2013).