CMT Seminar: Andrew Mitchell

Postdoc at Institute for Theoretical Physics, Ütrecht University

Strong correlations, from quantum dots to molecules
Electronic interactions in nanostructures produce distinctive signatures in transport, as widely observed in quantum dot devices and also single-molecule junctions. The Kondo effect is a classic paradigm, where low-temperature spin-flip scattering leads to the celebrated zero-bias anomaly. But more exotic physics can be realized in systems with additional orbital structure or when different screening channels compete. I will discuss our theory [1], describing very recent charge-Kondo experiments [2]. The quantitative agreement between theory and experiment over 9 orders of magnitude unambiguously demonstrates that a frustrated quantum critical state involving a free Majorana fermion is realized in the device. Exact predictions for the nonequilibrium conductance are also made. In the context of single-molecule junctions, I will show how the interplay between strong interactions and quantum interference can give rise to low-temperature conductance nodes by a novel 'Kondo Blockade' mechanism [3].

[1] Mitchell, Landau, Fritz, Sela, PRL 116, 157202 (2016)
[2] Iftikah et al., Nature 526, 233 (2015)
[3] Mitchell, Pedersen, Hedegård, Paaske (in preparation)