TY  - JOUR
A1  - Mor, Selene
A1  - Herzog, Marc
A1  - Noack, Johannes
A1  - Katayama, Naoyuki
A1  - Nohara, Minoru
A1  - Takagi, Hide
A1  - Trunschke, Annette
A1  - Mizokawa, Takashi
A1  - Monney, Claude
A1  - Stähler, Julia
T1  - Inhibition of the photoinduced structural phase transition in the excitonic insulator Ta2NiSe5
JF  - Physical review : B, Condensed matter and materials physics
N2  - Femtosecond time-resolved midinfrared reflectivity is used to investigate the electron and phonon dynamics occurring at the direct band gap of the excitonic insulator Ta2NiSe5 below the critical temperature of its structural phase transition. We find that the phonon dynamics show a strong coupling to the excitation of free carriers at the Gamma point of the Brillouin zone. The optical response saturates at a critical excitation fluence F-C = 0.30 +/- 0.08 mJ/cm(2) due to optical absorption saturation. This limits the optical excitation density in Ta2NiSe5 so that the system cannot be pumped sufficiently strongly to undergo the structural change to the high-temperature phase. We thereby demonstrate that Ta2NiSe5 exhibits a blocking mechanism when pumped in the near-infrared regime, preventing a nonthermal structural phase transition.
Y1  - 2018
U6  - https://doi.org/10.1103/PhysRevB.97.115154
SN  - 2469-9950
SN  - 2469-9969
VL  - 97
IS  - 11
PB  - American Physical Society
CY  - College Park
ER  -