Role of matrix elements in the time-resolved photoemission signal

Authors :: Boschini, F.
Bugini, D.
Zonno, M.
Michiardi, M.
Day, R. P.
Razzoli, E.
Zwartsenberg, B.
Neto, E. H. da Silva
Conte, S. dal
Kushwaha, S. K.
Cava, R. J.
Zhdanovich, S.
Mills, A. K.
Levy, G.
Carpene, E.
Dallera, C.
Giannetti, C.
Jones, D. J.
Cerullo, G.
Damascelli, A.
Source :: New J. Phys. 22 023031 (2020)
Publication Year :: 2018
Abstract: Time- and angle-resolved photoemission spectroscopy accesses the ultrafast evolution of quasiparticles and many-body interactions in solid-state systems. However, the momentum- and energy-resolved transient photoemission intensity may not be unambiguously related to the intrinsic relaxation dynamics of photoexcited electrons. In fact, interpretation of the time-dependent photoemission signal can be affected by the transient evolution of both the one-electron removal spectral function as well as the photoemission dipole matrix elements. Here we investigate the topological insulator Bi$_{1.1}$Sb$_{0.9}$Te$_2$S to demonstrate, by means of a careful probe-polarization study, the transient contribution of matrix elements to the time-resolved photoemission signal.<br />Comment: 7 pages, 3 figures