[Seminar] Mr. Jonas Habel "Bloch Oscillations Revisited: Beyond Charge Transport"

Speaker

Mr. Jonas Habel / Technical University of Munich

Title

Bloch Oscillations Revisited: Beyond Charge Transport

Abstract

In 1928, Felix Bloch predicted that an electron wavepacket in a perfect crystalline conductor subject to a static electric field would oscillate locally rather than drift along the field direction, resulting in zero net electric current. This phenomenon, now called Bloch oscillations (BOs), is one of the more surprising consequences of quantum band theory, defying everyday intuition (just flick a light switch) and well-established relations like Ohm’s law. Nonetheless, BOs have since been experimentally observed in multiple solid-state systems.

The literature focuses predominantly on the electric current as the primary observable of BOs. However, electrons in real materials generally couple to all sorts of other degrees of freedom (d.o.f.). It is therefore natural to ask whether BOs also occur in observables distinct from the electric current.

The answer is indeed yes, BOs are more widespread than anticipated! To exemplify the mechanism, we consider magnetic observables in unconventional (higher-wave) magnets, which have recently attracted significant attention due to their strong coupling of charge and spin d.o.f. We also demonstrate how to explore our predicted effects in the lab using state-of-the-art ultrafast spectroscopy experiments.

The outline of my talk is as follows: First, I will review BOs and their theoretical description in terms of transport theory, as well as unconventional magnets and their relevant properties. Then, I’m going to present our recent work which demonstrates magnetic BOs in p-wave magnets, and our work in progress on spin current BOs in d-wave magnets (aka “altermagnets”). I will close with an outlook on further novel BO effects, challenges in the theoretical description, and a glimpse of real-life applicability.

Profile of Speaker

I am a fourth-year PhD student in the group of Prof. Johannes Knolle at Technical University of Munich, Germany. My research is centered around quantum magnetism, with a focus on the effects of magnon-magnon interations in ordered but strongly frustrated magnets. Recently I've been delving into the field of unconventional magnets and studying their far-from-equilibrium quantum dynamics.

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Meeting ID: 923 3701 1269
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