Single-gate tracking behavior in flat-band multilayer graphene devices with Cyprian Lewandowski

A central feature of many van der Waals (vdW) materials is the ability to precisely control their charge doping, n, and electric displacement field, D, using top and bottom gates. For devices composed of only a few layers, it is commonly assumed that D causes the layer-by-layer potential to drop linearly across the structure. Here, we show that this assumption fails for a broad class of crystalline and moiré vdW structures based on Bernal- or rhombohedral-stacked multilayer graphene. We find that the electronic properties at the Fermi level are largely dictated by special layer—polarized states arising at Bernal-stacked crystal faces, which typically coexist in the same band with layer-delocalized states.  We uncover a novel mechanism by which the layer-delocalized states completely screen the layer--polarized states from the bias applied to the remote gate. This screening mechanism leads to an unusual scenario where voltages on either gate dope the band as expected, yet the band dispersion and associated electronic properties remain primarily (and sometimes exclusively) governed by the gate closer to the layer--polarized states. Our results reveal a novel electronic mechanism underlying the atypical single-gate–-controlled transport characteristics observed across many flat-band graphitic structures, and provide key theoretical insights essential or accurately modelling these systems.

Please note that while seminars typically take place in Compton 241, this event has been moved to the Physics Library (Compton 340)

Cyprian's seminar is accompanied by an additional event for students at 12pm in Compton 340:
Physics Careers & Navigating Your Path
Physics degree holders are highly employable in both the private and public sectors. However, students and early career scientists may be unaware of non-academic career pathways that exist within industry. This talk will provide an overview and examples of common career paths taken by physics degree holders, as well as give resources to assist with career exploration and the job search.