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11.07.2022 - 15.07.2022, Celeste Hotel, on UCF main campus, Orlando, Florida
05.09.2022 - 09.09.2022, Iseolago hotel, Iseo, Italy.


MUST2022 Conference- succesfully concluded
New scientific highlights- by MUST PIs Chergui and Richardson
FELs of Europe prize for Jeremy Rouxel- “Development or innovative use of advanced instrumentation in the field of FELs”
Ruth Signorell wins Doron prizefor pioneering contributions to the field of fundamental aerosol science
New FAST-Fellow Uwe Thumm at ETH- lectures on Topics in Femto- and Attosecond Science
International Day of Women and Girls in Science- SSPh asked female scientists about their experiences
New scientific highlight- by MUST PIs Milne, Standfuss and Schertler
EU XFEL Young Scientist Award for Camila Bacellar,beamline scientist and group leader of the Alvra endstation at SwissFEL
Prizes for Giulia Mancini and Rebeca Gomez CastilloICO/IUPAP Young Scientist Prize in Optics & Ernst Haber 2021
Nobel Prize in Chemistry awarded to RESOLV Member Benjamin List- for the development of asymmetric organocatalysis
NCCR MUST at Scientifica 2021- Lightning, organic solar cells, and virtual molecules
#NCCRWomen- NCCR MUST celebrates 50 years women’s right to vote in Switzerland
Kick-Off dynaMENT Mentoring for Women in Natural Sciences- with Ursula Keller as plenary speaker

Structural involvement in the melting of the charge density wave in 1T−TiSe2

March 1, 2021

It is commonly assumed that electronic phenomena occur at faster time scales than structural rearrangements. Here, we show the opposite: weak electronic excitations induce atomic displacements that outpace purely electronic charge carrier-interactions and hence are the dominant contribution in melting of the charge-density wave (CDW) in TiSe2. This divergence of electronic and structural order is directly observed in experimental data from a transient ultrafast resonant/non-resonant X-Ray diffraction experiment. Our results create a  paradigm shift that constitute a different, mechanistic pathway for phase transitions in the ultrafast regime.

Fig. 1. CDW phase and associated PLD upon cooling of 1TTiSe2. (a) Simplified Fermi surface of a slice through Fermi pockets of holes (red, Se 4p) and electrons (blue, Ti 3d) in the first Brillouin zone at ±A along the kc axis, shown in the room-temperature (left) and CDW (right) phase. The band-folding of Ti 3d and Se 4p states accompanying the CDW transition is indicated, leading to a re-referencing of the Brillouin zone (e.g., the RT L point becomes CDW L/Γ point). (b) The 3D representation of the bands illustrates the pd splitting between the folded Se 4p and Ti 3d bands at L/Γ, leading to excitonic correlations between electron-hole pairs (black dotted circle). (c) PLD associated with the CDW phase, causing a doubling of the unit cell along all three dimensions.
Reference: Burian, M., Porer, M., Mardegan, J.R.L., Esposito, V., Parchenko, S., Burganov, B., Gurung, N., Ramakrishnan, M., Scagnoli, V., Ueda, H., Francoual, S., Fabrizi, F., Tanaka, Y., Togashi, T., Kubota, Y., Yabashi, M., Rossnagel, K., Johnson, S.L., and Staub, U. (2021). Structural involvement in the melting of the charge density wave in 1T−TiSe2. Phys Rev Research 3, 013128. (10.1103/PhysRevResearch.3.013128)

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