| Title: | Dissecting Mott and charge-density wave dynamics in the photoinduced phase of 1T-TaS[sub]2 |
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| Authors: | ID Simoncig, Alberto (Author)
ID Stupar, Matija (Author)
ID Ressel, Barbara (Author)
ID Saha, Tanusree (Author)
ID Rebernik Ribič, Primož (Author)
ID De Ninno, Giovanni (Author) |
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| Files: |
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| Language: | English |
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| Work type: | Unknown |
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| Typology: | 1.01 - Original Scientific Article |
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| Organization: | UNG - University of Nova Gorica
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| Abstract: | The two-dimensional transition-metal dichalcogenide 1T−TaS2 is a complex material standing out for its puzzling low temperature phase marked by signatures amenable to both Mott-insulating and charge-density wave states. Electronic Mott states, coupled to a lattice, respond to coherent optical excitations via a modulation of the lower (valence) Hubbard band. Such dynamics is driven by strong electron-phonon coupling and typically lasts for tens of picoseconds, mimicking coherent structural distortions. Instead, the response occurring at the much faster timescale, mainly dominated by electronic many-body effects, is still a matter of intense research. By performing time- and angle-resolved photoemission spectroscopy, we investigated the photoinduced phase of 1T−TaS2 and found out that its lower Hubbard band promptly reacts to coherent optical excitations by shifting its binding energy towards a slightly larger value. This process lasts for a time comparable to the optical pump pulse length, mirroring a transient change of the onsite Coulomb repulsion energy (U). Such an observation suggests that the correction to the bare value of U, ascribed to the phonon-mediated screening which slightly opposes the Hubbard repulsion, is lost within an interval of a few tens of femtoseconds and can be understood as a fingerprint of electronic states largely decoupled from the lattice. Additionally, these results enforce the hypothesis, envisaged in the current literature, that the transient photoinduced states belong to a sort of crossover phase instead of an equilibrium metallic one. |
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| Keywords: | ultrafast phenomena, time resolved photoemission, strongly correlated systems, transition metal dichalcogenide |
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| Year of publishing: | 2021 |
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| Number of pages: | str. 1-7 |
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| Numbering: | Vol. 103, iss. 5 |
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| PID: | 20.500.12556/RUNG-6471 |
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| COBISS.SI-ID: | 59328771 |
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| UDC: | 53 |
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| ISSN on article: | 2469-9950 |
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| DOI: | 10.1103/PhysRevB.103.155120 |
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| NUK URN: | URN:SI:UNG:REP:OCCSHWAX |
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| Publication date in RUNG: | 13.04.2021 |
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| Views: | 2394 |
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| Downloads: | 0 |
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