ELFT HÍRADÓ

[<vera.horvath AT eli-alps.hu>]

Meghívó az ELI-ALPS szemináriumára

Előadó: Mousumi Upadhyay-Kahaly
Az előadás címe: Ultrafast electron processes in two-dimensional structures

Időpont: 2018. január 12., 9 óra
Helyszín: az ELI-ALPS konferenciaterme (Szeged, Budapesti út 5.)

Az előadás tartalmi összefoglalója:
Recent graphene research has triggered enormous interest in new two-
dimensional ordered crystals constructed by the inclusion of elements other
than carbon for bandgap opening and controlled engineering. Suitable design of
superior multifunctional two-dimensional materials with proper and tunable
bandgap has wide-ranging applications, such as in opto-electronics. In these
systems, usually the  energy dispersion relation of massive relativistic
particles is characterized by a gradual transition from parabolic to linear
momentum dependence, which could be easily triggered through suitable doping
or intercalation, structure modifications or strain engineering. Possibilities
of easy tuning the effective mass of the Dirac Fermions makes these systems
appealing for investigating strong-field and ultrafast dynamics and nonlinear
behavior of electrons.

In this presentation, we would discuss the nonlinear optical response of
electrons in pseudorelativistic energy bands, as offered by the class of two-
dimensional materials.Upon addressing the structure-function relationships in
two-dimendional materials such as graphene, and phosphorene, using first
principles density functional theory and time dependent density functional
theory, we demonstrate that the relativistic nature of the band structure is
crucial for the nonlinear response, which vanishes identically in the strictly
nonrelativistic limit of parabolic bands. We would discuss how the resulting
modification in electronic properties has prominent implication on the local
charge densities, allowed inter-band, intra-band transitions and therefore the
inherent ultrafast electron dynamics.

A szeminárium angol nyelvű. Minden érdeklődőt szívesen látunk.