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arXiv · 1702.05300

Ultrafast doublon dynamics in photo-excited 1T-TaS$_2$

Manuel Ligges·Isabella Avigo·Denis Golež·Hugo Strand·Ljupka Stojchevska·Matthias Kalläne·Ping Zhou·Kai Rossnagel·Martin Eckstein·Philipp Werner·Uwe Bovensiepen
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Abstract

Strongly correlated systems exhibit intriguing properties caused by intertwined microscopic in- teractions that are hard to disentangle in equilibrium. Employing non-equilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1T-TaS$_2$, we identify a spectroscopic signature of double occupied sites (doublons) that are reflects fundamental Mott physics. Doublon-hole recombination is estimated to occur on time scales of one electronic hopping cycle $\hbar/J\approx$ 14 fs. Despite strong electron-phonon coupling the dynamics can be explained by purely electronic effects captured by the single band Hubbard model, where thermalization is fast in the small-gap regime. Qualitative agreement with the experimental results however requires the assumption of an intrinsic hole-doping. The sensitivity of the doublon dynamics on the doping level provides a way to control ultrafast processes in such strongly correlated materials.

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Manuel Ligges, Isabella Avigo, Denis Golež, Hugo Strand, Ljupka Stojchevska, Matthias Kalläne, Ping Zhou, Kai Rossnagel, Martin Eckstein, Philipp Werner, Uwe Bovensiepen. 2017-02-17. Ultrafast doublon dynamics in photo-excited 1T-TaS$_2$. https://doi.org/10.1103/physrevlett.120.166401

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