## Research

# Annual Reports

# Andrei Manolescu

My research in physics is orriented to theoretical modelling and numerical calculations of quantum-mechanical electronic properties of semiconductor nanostructures. I worked on the following subjects: two-dimensional systems in magnetic fields, screening, exchange, and other many-body Coulomb phenomena, edge states, transport and electromagnetic absorption in modulated systems, electronic states in periodic electric and magnetic fields, spin splitting, magnetization. At present I am mostly involved in modelling transient currents and time dependent electronic transport in two-dimensional structures of nanometric size.

# Ágúst Valfells

I am interested in nano- and microscale vacuum electronics. In devices of this magnitude the mean free path for electrons is greater than the length scale of the device even under atmospheric pressure. There are many similarites to the well known behaviour of macroscopic counterparts, but at the small scale many effects which are neglected in the macroscopic regime become quite important, e.g. Coulomb collisional effects, field emission, surface roughness and quantum effects to name a few. Lately I have been investigating space-charge effects in this regime. Recent discoveries include a new mechanism for generating oscillating current in a diode, with easily tunable frequency in the THz range; and also simple new scaling laws for space-charge limited emission from cylindrical and spherical emitters.

# Halldór G. Svavarsson

My research areas of expertise include nanolithography, nanophotonics, nanoplasmonics, optical bio- and chemical sensors, nanofabrication, integrated nanoscale devices and thin-films. In particular I have been focusing on fabrication and characterization of periodic nanostructures of metals, dielectrics and semiconductors for thermoelectric, photovoltaic and photonic applications and with a special emphasize on silicon nanowires (SiNWs). These researches have been done in close collaboration with the Nanophotonics Device group at the Electrical Engineering department of the University of Texas at Arlington (http://leakymoderesonance.com/).

# Sigurður I. Erlingsson

The focus of my reseach is theoretical condensed matter physics. I've worked on the effects of hyperfine interaction on spin dynamics in GaAs quantum dots. The role played by the Rashba spin-orbit interaction in transport in semiconductor nanostructure is something I've studied for a few years now. In order to highlight the role played by the the spin-orbit interaction I've worked on multiterminal systems (the spin-Hall effect) and transport throught periodic potential in a two terminal setup. I've also working on novel interface phenomena in magnetotransport in metallic spin-valve systems using resistor network model. More recently I've started working on topological isulators.