Greetings from Bangkok.
Welcome to hybrid seminars in condensed matter physics at Mahidol University. The seminars are informal and meant to inspire discussions. If you would like to participate, please sign up to receive seminar announcements or contact us at kitinan.pon@mahidol.ac.th.
This semester, the seminars start at 10:30 (Thailand time) every Tuesday, unless otherwise announced.
Upcoming Seminar
15.09.2026
Speaker: Dwaipayan Paul
Time: 12:30-13:30
Venue: online
Title: Coulomb drag driven electron-hole bifluidity and negative mobility in doped graphene
Abstract: In this talk, I will discuss the curious phenomenon of negative differential conductivity and hydrodynamic transport of charge carriers in doped graphene, connected to some recent measurements. To probe this physics, we extend the ab initio elphbolt transport code to include the Coulomb collision integral. We find that the strong Coulomb interactions can not only drive the individual hydrodynamics in the electron and hole subsystems, but also the far more exotic joint electron-hole bifluidity. Furthermore, we observe a strong violation of the Wiedemann-Franz law closer to the charge neutrality condition. These findings establish the roles of microscopic scattering mechanisms for achieving the hydrodynamic transport state in electron-hole systems. I will further discuss the computational challenges and our ongoing efforts in extending this work.