Untersuchung und Kontrolle Exzitonischer Quantenkorrelationen ( Emmy Noether)

  • Huber, Rupert - Project leader
  • Department of Physics
    Pashkin, Alexej; Kübler, Carl; Ehrke, Henri; Lopez, Ricardo; Halabica, Andrej; Haglund, Richard; Huber, Rupert; Leitenstorfer, Alfred (2011): Ultrafast insulator-metal phase transition in VO2 studied by multiterahertz spectroscopy Physical Review B. 2011, 83(19). ISSN 1098-0121. Available under: doi: 10.1103/PhysRevB.83.195120

Ultrafast insulator-metal phase transition in VO2 studied by multiterahertz spectroscopy


The ultrafast photoinduced insulator-metal transition in VO2 is studied at different temperatures and excitation fluences using multi-THz probe pulses. The spectrally resolved midinfrared response allows us to trace separately the dynamics of lattice and electronic degrees of freedom with a time resolution of 40 fs. The critical fluence of the optical pump pulse, which drives the system into a long-lived metallic state, is found to increase with decreasing temperature. Under all measurement conditions, we observe a modulation of the eigenfrequencies of the optical phonon modes induced by their anharmonic coupling to the coherent wave-packet motion of V-V dimers at 6.1 THz. Furthermore, we find a weak quadratic coupling of the electronic response to the coherent dimer oscillation resulting in a modulation of the electronic conductivity at twice the frequency of the wave-packet motion. The findings are discussed in the framework of a qualitative model based on an approximation of local photoexcitation of the vanadium dimers from the insulating state.

Origin (projects)

Funding sources
Name Finanzierungstyp Kategorie Project no.
Schwerpunktprogramm third-party funds research funding program 414/10
Further information
Period: 15.12.2009 – 31.12.2010