Berlin 2024 – wissenschaftliches Programm

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PLV: Plenarvorträge

PLV IV

PLV IV: Plenarvortrag

Dienstag, 19. März 2024, 08:30–09:15, H 0105

Capturing light induced phase transitions with femtosecond movies — •Nuh Gedik — Massachusetts Institute of Technology, Cambridge, MA, USA

Materials typically undergo phase changes as a function of external parameters such as temperature, pressure or magnetic field. Light can also be used to both switch between equilibrium phases and to create new photo-induced states that may have no equilibrium counterparts. Even though there are fascinating examples of photoinduced phase transitions, the detailed microscopic mechanisms and overarching principles that govern these are still not known. In this talk, I will present two recent examples that advance our understanding of this phenomena. First, I will describe how we used ultrashort laser pulses to capture light induced melting and recovery of a charge density wave phase with femtosecond time resolution. During this process, a new state that does not exist in equilibrium is also transiently created. Secondly, I will show experiments in which high field THz pulses are used to induce metastable magnetization in a layered antiferromagnet. Understanding light induced phase transitions could pave the way for optical engineering of new quantum states of matter.

Keywords: Light induced phase transitions; Ultrafast electron diffraction; High field Thz spectroscopy; Pump Probe spectroscopy; Layered materials