DCMPMS Seminars
Realizing Atomic Resolution Vibrational Spectroscopy
by Dr. Kartik Venkatraman (Center for Nanophase Materials Sciences, Oak Ridge National Laboratory)
Monday, December 6, 2021
from
to
(Asia/Kolkata)
at Zoom link : https://zoom.us/j/98486388327 Meeting ID : 984 8638 8327 Passcode : 784120
at Zoom link : https://zoom.us/j/98486388327 Meeting ID : 984 8638 8327 Passcode : 784120
Zoom link : https://zoom.us/j/98486388327
Meeting ID : 984 8638 8327 Passcode : 784120
Description |
Vibrational spectroscopy has become a ubiquitous characterization tool in materials science, revealing compositional information and yielding spectral fingerprints for atomic bonding arrangements. Traditional vibrational spectroscopies based on infrared photon absorption, visible photon scattering, and inelastic neutron scattering boast of sub-meV energy resolution but suffer from poor (~1 μm) spatial resolution. Near-field infrared and optical vibrational spectroscopies have demonstrated significant improvement in spatial resolution, routinely yielding ~50 nm. Such spatial resolution still limits characterization of individual nanoparticles or atomic to nanoscale heterogeneities like defects and interfaces in materials. In 2014, a novel vibrational spectroscopy was realized which combines 1Å spatial resolution routinely achievable in an aberration-corrected scanning transmission electron microscope (STEM) with 3 – 8 meV energy resolution achievable using monochromated electron energy-loss spectroscopy (EELS). Since its realization, vibrational spectroscopy with monochromated STEM EELS has seen tremendous progress like performing damage-free nanoscale detection for both organic and inorganic specimens, measuring temperature in nanometer-sized areas with 1 K precision, determining the phonon dispersion in individual nanoparticles, demonstrating atomic resolution, etc., which has impacted a wide variety of important scientific problems. In this talk, I will present my contribution to this field interlaced with seminal contributions from researchers all around the world. |