OSE Seminar by Dr. Prashant Padmanabhan on Exploring Magnetic Dynamics and Collective Phenomena in Quantum Materials
Departmental News
Posted: November 30, 2022
Date: Thursday, 12/01/2022
Time: 12:15 PM - 1:15 PM
Location: PAIS, Room 2540
Abstract:
The first demonstration of transient demagnetization after femtosecond optical excitation was a seminal achievement in condensed matter physics leading to the birth of the field of ultrafast magnetism. Today, we continue to work towards unravelling the nature of the mechanisms that underlie these processes and exploit them to harness new magnetic phenomena. Quantum material systems hosting novel intrinsic magnetic order represent an exciting new playground to study the transient interactions between photons and spin excitations in ordered phases. In this talk, I will discuss our efforts in using such systems to both control the properties of electromagnetic radiation and coherently drive collective magnetic phenomena with light, focusing on three examples. First, I will highlight how terahertz pulses can be manipulated by leveraging magneto-plasmonic resonances in micro-structured graphene. We will then examine how light can be used to coherently manipulate magnetic order through the dynamic quenching of magneto-crystalline anisotropy in the multiferroic skyrmion-host GaV4S8. Finally, I will discuss our recent work involving the ferromagnetic van der Waals crystal CrI3. Here, we shed light on the nature of angular momentum transfer in this material and reveal a strong dynamic coupling between the spin and lattice degrees of freedom. Together, these three examples codify the immense promise that ultrafast optics holds in understanding and utilizing the novel magnetic properties of quantum materials.
Biography:
Prashant Padmanabhan is a staff scientist at the Center for Integrated Nanotechnologies at Los Alamos National Laboratory. His research interests are centered upon the photoinduced manipulation of bulk and nanoscale materials possessing order, correlations, and topologically protected phases using an array of ultrafast spectroscopy techniques spanning the ultraviolet to terahertz (THz) regimes. His current efforts are aimed at uncovering the dynamics of the electronic, lattice, and spin degrees of freedom of van der Waals magnetic systems, the ultrafast opto-magnetic control of magnetic order, exploring THz emission from bulk and nanostructured materials, and nonlinear optical processes in low dimensional systems with structured light. Prashant received his Ph.D. in Applied Physics from the University of Michigan in 2014 focusing on coherent acoustic plasma oscillations in semiconductor heterostructures.
