Realizing new electronic transport regimes in van der Waals semiconductors
Milan Delor
Columbia University, New York, NY 10027, USA
Achieving ballistic, coherent charge and energy flow in materials at room temperature is a long-standing goal that could unlock lossless energy and information technologies. The key obstacle to overcome is short-range scattering between electronic particles and lattice vibrations (phonons). I will describe new avenues to realize ballistic electronic energy transport in two-dimensional (2D) semiconductors by harnessing hybridization between electronic particles and long-wavelength excitations. I will focus on a new mechanism in which strong interactions between electrons and delocalized phonons can result in the formation of 2D acoustic polarons. These polarons are intrinsically protected from scattering with phonons, resulting in sustained ballistic transport over macroscopic spatiotemporal scales even at room temperature, a remarkable phenomenon we are beginning to harness in electronic devices. To support this work, we develop ultrafast optical imaging capabilities enabling us to track the propagation of electronic and photonic quasiparticles with femtosecond resolution and few-nanometer sensitivity, providing a precise measurement of quasiparticle velocity, scattering pathways, and transition from coherent to incoherent transport.
Bio: Milan Delor is an Assistant Professor in the Department of Chemistry at Columbia University. He completed his PhD in 2014 at the University of Sheffield (with Prof. Julia Weinstein), where he focused on quantum control of molecular photophysics using multidimensional spectroscopy. In his postdoc at UC Berkeley (with Prof. Naomi Ginsberg), he developed new imaging technologies to track energy flow in semiconductors. He started his position at Columbia in 2019. His group focuses on light-matter interactions, with a special interest in identifying and controlling new electronic transport regimes and quantum phases in emerging materials. He is a recipient of the 2022 Beckman Young Investigator award.
