Analysis and control of electron dynamics, and the predictive power of time-dependent density-functional theory
Gedenkkolloquium für Prof. Dr. Reiner M. Dreizler
This lecture is about the motion of electrons on the
femto- and atto-second time scale; how it can be monitored, analyzed and,
ultimately, controlled with ultra-short laser pulses. Real-time simulations are
performed employing the ab-initio approach of time-dependent density functional
theory (TDDFT). The mathematical foundation of TDDFT is a Frankfurt invention
which evolved naturally from the specific scientific environment of the
Dreizler group in the 70s and 80s of the past century. The theory guarantees
that the time-dependent density of an interacting many-electron system can be
calculated, in principle exactly, from a system of single-particle Schrödinger
equations. Using TDDFT, we
shall visualize the laser-induced formation and breaking of chemical bonds in
real time, and we shall highlight non-steady-state
features of the electronic current through nano-scale junctions. In another
application, with the goal of pushing magnetic
storage processes towards faster and faster time scales, we have predicted that
in some magnetic materials, an optically induced spin transfer (OISTR) from one
magnetic sub-lattice to another can be triggered by short laser pulses. As an
all-optical process, OISTR is temporally limited only by the duration of the
laser pulse. OISTR was first predicted by TDDFT calculations and later found
experimentally. The OISTR effect marks the birth of “atto-magnetism". It allows
for switching times six orders of magnitude faster than present-day magnetic
read-write devices.
Local host: Prof.
Dr. Carsten Greiner
