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arXiv · 2003.12925

Observation of an excitonic Mott transition through ultrafast core-$\textit{cum}$-conduction photoemission spectroscopy

Maciej Dendzik·R. Patrick Xian·Enrico Perfetto·Davide Sangalli·Dmytro Kutnyakhov·Shuo Dong·Samuel Beaulieu·Tommaso Pincelli·Federico Pressacco·Davide Curcio·Steinn Ymir Agustsson·Michael Heber·Jasper Hauer·Wilfried Wurth·Günter Brenner·Yves Acremann·Philip Hofmann·Martin Wolf·Andrea Marini·Gianluca Stefanucci·Laurenz Rettig·Ralph Ernstorfer
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Abstract

Time-resolved soft-X-ray photoemission spectroscopy is used to simultaneously measure the ultrafast dynamics of core-level spectral functions and excited states upon excitation of excitons in WSe$_2$. We present a many-body approximation for the Green's function, which excellently describes the transient core-hole spectral function. The relative dynamics of excited-state signal and core levels reveals a delayed core-hole renormalization due to screening by excited quasi-free carriers, revealing an excitonic Mott transition. These findings establish time-resolved core-level photoelectron spectroscopy as a sensitive probe of subtle electronic many-body interactions and an ultrafast electronic phase transition.

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Maciej Dendzik, R. Patrick Xian, Enrico Perfetto, Davide Sangalli, Dmytro Kutnyakhov, Shuo Dong, Samuel Beaulieu, Tommaso Pincelli, Federico Pressacco, Davide Curcio, Steinn Ymir Agustsson, Michael Heber, Jasper Hauer, Wilfried Wurth, Günter Brenner, Yves Acremann, Philip Hofmann, Martin Wolf, Andrea Marini, Gianluca Stefanucci, Laurenz Rettig, Ralph Ernstorfer. 2020-03-29. Observation of an excitonic Mott transition through ultrafast core-$\textit{cum}$-conduction photoemission spectroscopy. https://doi.org/10.1103/physrevlett.125.096401

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