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  • Ultrafast electron calorimetry uncovers a new long-lived metastable state in 1 T -TaSe 2 mediated by mode-selective electron-phonon coupling
Title: Ultrafast electron calorimetry uncovers a new long-lived metastable state in 1 T -TaSe 2 mediated by mode-selective electron-phonon coupling
Quantum materials represent one of the most promising frontiers in the quest for faster, lightweight, energy-efficient technologies. However, their inherent complexity and rich phase landscape make them challenging to understand or manipulate. Here, we present a new ultrafast electron calorimetry technique that can systematically uncover new phases of quantum matter. Using time- and angle-resolved photoemission spectroscopy, we measure the dynamic electron temperature, band structure, and heat capacity. This approach allows us to uncover a new long-lived metastable state in the charge density wave material 1 T -TaSe 2 , which is distinct from all the known equilibrium phases: It is characterized by a substantially reduced effective total heat capacity that is only 30% of the normal value, because of selective electron-phonon coupling to a subset of phonon modes. As a result, less energy is required to melt the charge order and transform the state of the material than under thermal equilibrium conditions.  more » « less
Award ID(s):
1734006
PAR ID:
10091671
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Science Advances
Volume:
5
Issue:
3
ISSN:
2375-2548
Page Range / eLocation ID:
eaav4449
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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