Quantized Heat Flow as a Probe of Thermal Equilibration and Edge Structures of Quantum Hall Phases in Graphene

Saurabh Kumar Srivastav received his B.Sc. (Hons) in Physics from Banaras Hindu University, Varanasi, in 2015. After this, He joined the Department of Physics, Indian Institute of Science, Bengaluru, India, as an Integrated PhD student. He completed his PhD under the supervision of Prof. Anindya Das in 2022. His PhD thesis was focused on understanding the edge structure of the several integers and fractional quantum Hall (QH) phases realized in graphene-based devices. It turns out that by measuring the transport coefficients, one can determine the topological quantum numbers of edge modes and hence the bulk topological order of the integer and fractional quantum Hall (QH) phases. Saurabh mainly focused on the measurement of the quantized thermal Hall conductance instead of the conventional electrical conductance measurement because it can provide additional insight, which is limited in electrical conductance measurement. By measuring the thermal conductance of hole conjugate states in the asymptotic limit of the thermal equilibration, He successfully measured the exact number of the topological edge modes of these phases in graphene, which remained an open question for decades. His PhD research offers an efficient route to determine the exact topological order of non-abelian fractional quantum Hall states. In his postdoctoral research at the Weizmann Institute of Science with Prof. Eli Zeldov, Saurabh is utilizing the SQUID-on-tip magnetic and thermal imaging techniques to explore the novel electronic phases realized in two-dimensional materials and their hybrid devices.

Electronic properties of graphene.- Electron in Magnetic field Quantum Hall effect.- Device Fabrication and Measurement Setup.- Universal quantization of thermal conductance in graphene.- Vanishing thermal equilibration for hole conjugate fractional quantum Hall states in graphene.