Wednesday Colloquia

Edge equilibration in Graphene Quantum Hall

by Prof. Anindya Das (Indian Institute of Science, Bangalore)

Wednesday, May 5, 2021 from to (Asia/Kolkata)
at Online through ZOOM Webinar ( Zoom link: https://zoom.us/j/97963259354?pwd=ZFZsa2xqWGJSZW5pUjZPNkNqeGlEZz09 )
Meeting ID: 979 6325 9354 Pass code: 04072020
Description
Transport through edge-channels is responsible for conduction in quantum Hall (QH) phases. The equilibration among the edges dictates the electrical and thermal transport coefficients, and its robust quantization relies on the nature of equilibration. In this colloquium, I will discuss how the charge and energy equilibrations are intriguing in graphene QH. I will discuss the equilibration problems for two systems; (a) symmetry broken graphene p-n junction with co-propagating edges, (b) fractional QH states with counter-propagating edge states. Our results pointing toward long-sought mesoscopic regimes, namely coherent regime in graphene p-n junction, and ballistic flow of charge mode along with a ballistic neutral mode (carry only energy but no charge) in the fractional QH states of graphene. At the end, I will discuss the future outlook of this field.

References:

1. Physical Review B 98 (15), 155421 (2018), 
2. Science Advances 5 (eaaw5798), 1-5 (2019), 
3. Communications Physics 3 (171), 1-7 (2020), 
4. Physical review letters (2021)