Theoretical studies on subfemtosecond dynamics of excited matters

Abstract

We introduce two aspects of the optical pulses (i.e., an audience watching the dynamics and a leading actor raising the dynamics) and demonstrate the interactions in terms of observations of real time-resolved responses and novel applications to open up the fastest electronics. First, we propose a new calculation tech-nique for the time-resolved photoemission spectroscopy that efficiently capture the real-time spectral weights of electronic structures of time-evolving single-particle Kohn-Sham orbitals in solid systems at the extremely ultrashort temporal space. It is found that the calculation can be used to explorer the non-equilibrium phase transitions of strongly correlated electron systems within the frame of the Tran-Blaha exchange potential so that it gives a new insight into the dynamical aspect of Zaanen-Sawatzky-Allen scheme in the case of excited CuO and NiO. We also introduce an appearance of pseudospin-correlated optical transitions in graphene and this would provide a chance to observe the dynamics of pseudospins in emerging materials. Second, control of electrons or their spins in the subfemtosecond time span could become a new pathway to the fastest elec-tronics or spintronics based on the light-wave-induced dynamics. We shall see the applied strain in wide-gap semiconductors is found to be a useful application to manipulate the light-wave-induced current in terms of change in effective mass as a controlling parameter. Also, we provide a smart heterojunction between 2D ferromagnetic transition metal tri-chalcogenide and non-magnetic semiconductor is shown as a petahertz spin device that generate spin filtered current or injector under the strong optical field. We believe our studies on the real-time dynamics provides an unexplored and undefined aspect induced by the optical pulses and suggests new guidance to the meaningful subfemtosecond physics.