Self-amplified photo-induced gap quenching in a correlated electron material
Author(s)Mathias, S.; Eich, S.; Urbancic, J.; Michael, S.; Carr, A. V.; Emmerich, S.; Stange, A.; Popmintchev, T.; Wiesenmayer, M.; Ruffing, A.; Jakobs, S.; Hellmann, S.; Matyba, P.; Chen, C.; Kipp, L.; Bauer, M.; Kapteyn, H. C.; Schneider, H. C.; Rossnagel, K.; Murnane, M. M.; Aeschlimann, M.; Rohwer, Timm; ... Show more Show less
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Capturing the dynamic electronic band structure of a correlated material presents a powerful capability for uncovering the complex couplings between the electronic and structural degrees of freedom. When combined with ultrafast laser excitation, new phases of matter can result, since far-from-equilibrium excited states are instantaneously populated. Here, we elucidate a general relation between ultrafast non-equilibrium electron dynamics and the size of the characteristic energy gap in a correlated electron material. We show that carrier multiplication via impact ionization can be one of the most important processes in a gapped material, and that the speed of carrier multiplication critically depends on the size of the energy gap. In the case of the charge-density wave material 1T-TiSe[subscript 2], our data indicate that carrier multiplication and gap dynamics mutually amplify each other, which explains—on a microscopic level—the extremely fast response of this material to ultrafast optical excitation.
DepartmentMassachusetts Institute of Technology. Department of Physics; Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology)
Nature Publishing Group
Mathias, S. et al. “Self-Amplified Photo-Induced Gap Quenching in a Correlated Electron Material.” Nature Communications 7 (2016): 12902. © 2016 Macmillan Publishers Limited
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