Abstract
Non-trivial Bloch band overlaps endow rich phenomena to a wide variety of quantum materials. The most prominent example is a transverse current in the absence of a magnetic field (i.e. the anomalous Hall effect). Here we show that, in addition to a dc Hall effect, anomalous Hall materials possess circulating currents and cyclotron motion without magnetic field. These are generated from the intricate wavefunction dynamics within the unit cell. Curiously, anomalous cyclotron motion exhibits an intrinsic decay in time (even in pristine materials) displaying a characteristic power law decay. This reveals an intrinsic dephasing similar to that of inhomogeneous broadening of spins. Circulating currents can manifest as the emission of circularly polarized light pulses in response to an incident linearly polarized (pulsed) electric field, and provide a direct means of interrogating a type of Zitterbewegung of quantum materials with broken time reversal symmetry.
Highlights
In the presence of a perpendicular magnetic field, electrons in a two dimensional electron gas experience a fast cyclotron motion owing to the Lorentz force
We show that in addition to a slow transverse drift arising from anomalous velocity (AV), anomalous Hall materials exhibit fast dynamics with a characteristic anomalous cyclotron-like motion without magnetic field
Similar to how slow guiding center motion (Hall drift) and fast cyclotron motion in the presence of a magnetic field are dual to each other, the slow transverse drift from semiclassical AV in anomalous Hall materials possesses an analogous duality to the fast anomalous cyclotron motion (ACM) we describe here
Summary
In the presence of a perpendicular magnetic field, electrons in a two dimensional electron gas experience a fast cyclotron motion owing to the Lorentz force. We show that in addition to a slow transverse drift arising from AV, anomalous Hall materials exhibit fast dynamics with a characteristic anomalous cyclotron-like motion without magnetic field. Even when the valence band is initially fully occupied, signatures of the pulse-activated pseudo-spin precession persist and manifest as a real-space cyclotron motion (of the entire electron gas).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
