PhD and Post Doc Quantum Seminar Series: Wei Yuan

This Spring semester the QUIEST Center is continuing to expand its new seminar series geared towards PhD and Post Doc students across SEAS and SAS to present on quantum-related topics of their choosing. Read on for more information on this week’s seminar presentation:

Presentation by:

Wei Yuan, Scientist at Goeppert LLC (Pennovation Center)

Talk Title:

Electrical Switching the Charility of Ciral Edge Current in Qauntum Anomalous Hall Insulators

Description:

A quantum anomalous Hall (QAH) insulator is a topological state of matter, in which the interior is insulating but electrical current flows along the edges of the sample, in either right-handed or left-handed direction dictated by the spontaneous magnetization orientation. In this work, we fabricate mesoscopic QAH sandwich Hall bar devices and find the QAH effect persists in a device with width of ~ 72nm. The effective magnetic exchange gap becomes narrower with reducing the Hall bar width. We succeed in switching the chiral edge current (CEC) chirality in QAH insulators through spin-orbit torque (SOT) by applying a current pulse under a suitably controlled gate voltage. The well-quantized QAH states before and after SOT switching with opposite CEC chiralities are demonstrated through our transport measurements. The SOT switching can be generated by both bulk and surface carriers in QAH insulators. Our work will not only advance our knowledge in the interplay between magnetism and topological states but also expedite easy and instantaneous manipulation of the QAH state in proof-of-concept energy-efficient electronic and spintronic devices as well as quantum information applications.