TY  - JOUR
A1  - Mor, Selene
A1  - Herzog, Marc
A1  - Golez, Denis
A1  - Werner, Philipp
A1  - Eckstein, Martin
A1  - Katayama, Naoyuki
A1  - Nohara, Minoru
A1  - Takagi, Hide
A1  - Mizokawa, Takashi
A1  - Monney, Claude
A1  - Staehler, Julia
T1  - Ultrafast Electronic Band Gap Control in an Excitonic Insulator
JF  - Physical review letters
N2  - We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta2NiSe5 investigated by time-and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of F-C = 0.2 mJ cm(-2), the band gap narrows transiently, while it is enhanced above FC. Hartree-Fock calculations reveal that this effect can be explained by the presence of the low-temperature excitonic insulator phase of Ta2NiSe5, whose order parameter is connected to the gap size. This work demonstrates the ability to manipulate the band gap of Ta2NiSe5 with light on the femtosecond time scale.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevLett.119.086401
SN  - 0031-9007
SN  - 1079-7114
VL  - 119
SP  - 11559
EP  - 11567
PB  - American Physical Society
CY  - College Park
ER  -