Lehrstuhlseminar Theoretische Physik II

10.5.2017 10:00, Raum: T-2003
PD Dr. Sergey Mikhailov (Theoretische Physik II)
Nonperturbative quasiclassical theory of the nonlinear electrodynamic response of graphene

An electromagnetic response of a single graphene layer to a uniform, arbitrarily strong electric field E(t) is calculated by solving the kinetic Boltzmann equation within the relaxation-time approximation. The theory is valid at low (microwave, terahertz, infrared) frequencies satisfying the condition ℏω ≲ 2E_F, where E_F is the Fermi energy. We investigate the saturable absorption and higher harmonics generation effects, as well as the transmission, reflection, and absorption of radiation incident on the graphene layer, as a function of the frequency and power of the incident radiation and of the ratio of the radiative to scattering damping rates. We show that the optical bistability effect, predicted in Phys. Rev. B 90, 125425 (2014) on the basis of a perturbative approach, disappears when the problem is solved exactly. We show that under the action of a high-power radiation (≳ 100kW/cm^2) both the reflection and absorption coefficients strongly decrease and the layer becomes transparent.

17.5.2017 10:00, Raum: T-2003
Simon Rittel (Bachelor Physik)
Das eindimensionale Ising-Modell
24.5.2017 10:00, Raum: T-2003
Domink Seibold (Bachelor Physik)
Das Heisenberg-Modell: Molekular-Feld Approximation, Phasenübergang, Entwicklung nahe Tc
31.5.2017 10:00, Raum: T-2003
Milan Harth (Theoretische Physik II)
Thermoelektrische Eigenschaften von Schichtstrukturen
7.6.2017 10:00, Raum: T-2003
Dominik Meidert (Bachelor Mathematik & Physik)
Kinetische Boltzmann-Theorie für verdünnte Gase
22.9.2017 14:00, Raum: R-506
Jakob Bonart (Theoretische Physik III)
Scaling behavior in confining potentials