ARPES - Theory and Applications
Wednesday, June 10th, 2020 @ 11 AM (AEST)
Time and angle-resolved photoelectron spectroscopy (Tr-ARPES) can map the full band structure of a material, including both the occupied and the unoccupied bands. This makes it possible to uncover important new information about the static and dynamic properties of materials.
After exciting a material with a femtosecond laser, time-resolved ARPES can map out the normally-empty conduction band to accurately measure the bandgap. In addition, by tuning the laser excitation fluence, new states and phases in both magnetic and quasi-2D charge density wave (CDW) materials can be uncovered.
ARPES is arguably the most powerful method for probing the electronic structure of solids to gain insight into a number of properties such as conductivity, magnetoresistance, superconductivity and magnetism laying the framework for applications ranging from solar cells, photocathodes and catalysis to spintronics, topological materials and quantum technologies.
![Data preview 2](https://www.kmlabs.com/hs-fs/hubfs/Data%20preview%202.jpg?width=350&name=Data%20preview%202.jpg) ![Data preview 3](https://www.kmlabs.com/hs-fs/hubfs/Data%20preview%203.jpg?width=350&name=Data%20preview%203.jpg)
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Speakers
Prof. Henry Kapteyn and Prof. Margaret Murnane, University of Colorado at Boulder
![Margaret Portrait](https://www.kmlabs.com/hs-fs/hubfs/Margaret%20Portrait.jpg?width=184&name=Margaret%20Portrait.jpg) Henry Kapteyn and Margaret Murnane are Professors of Physics at the University of Colorado at Boulder, and fellows of JILA - a research institute joint between the University of Colorado and NIST. Together they won the Benjamin Franklin Medal in 2020. Henry is a member of the US National Academy of Sciences, and Margaret is a Director of the National Science Foundation STROBE Center on Real Time Functional Imaging.
As long-term collaborators, Margaret and Henry have developed few-cycle femtosecond lasers, and “tabletop x-ray lasers” based on high harmonic upconversion.
References
[1] Y. Zhang et al., "Coherent modulation of the electron temperature and electron–phonon couplings in a 2D material," PNAS, p. 201917341, 2020, doi: 10.1073/pnas.1917341117. [2] X. Shi et al., "Ultrafast electron calorimetry uncovers a new long-lived metastable state in 1T-TaSe2 mediated by mode-selective electron-phonon coupling," Science Advances, vol. 5, p. eaav4449, 2019, doi: 10.1126/sciadv.aav4449. [3] P. Tengdin et al., "Direct light-induced spin transfer between different elements in a spintronic Heusler material via femtosecond laser excitation," Science Advances, vol. 6, p. eaaz1100, 2020, doi: 10.1126/sciadv.aaz1100 (2020). [4] W. You et al., "Revealing the universal nature of the ultrafast magnetic phase transition in Ni by correlating extreme ultraviolet magneto-optic and photoemission spectroscopies," Physical Review Letters, vol. 121, p. 077204, 2018, doi: 10.1103/PhysRevLett.121.077204. [5] P. Tengdin et al., "Critical Behavior within 20fs Drives the Out-of-Equilibrium Laser-induced Magnetic Phase Transition in Nickel," Science Advances, vol. 4, p. 9744, 2018, doi: 10.1126/sciadv.aap9744
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