Abstract
Electronic transport is studied at low temperatures in twodimensional electron gases (2DEGs) and in mesoscopic semiconductor microstructures.
The method of microwavedetection of the Shubnikovde Haas effect for the contactfree characterisation of transport properties of 2DEGs is explored using both magneticfield modulation and lightinduced carrier modulation. The methods are compared to magnetophotoluminescence (PL), cyclotron resonance (CR), optically detected CR, and to standard electrical measurements.
The effect of plasma dry etching of the surface of highmobility 2DEG samples on the properties of the 2DEG is studied. The PL and the transport properties of the 2DEG and the concentration of a paramagnetic surface defect created by the etching are found not to be correlated to each other.
The classical and the quantum mechanical dynamics of electrons in mesoscopic, open, triangular electron billiards is studied. The temperatureaveraged magnetoresistance can, using simulations, be explained by specific, classical electron trajectories, the relative importance of which is shown to depend on their Lyapunov stability. Quantum mechanical calculations reproduce observed conductance fluctuations which can be related to a specific electron orbit. Visualizations of the classical and the quantum mechanical electron density distribution inside the billiard are compared at various magnetic fields
The resistance of quasiballistic wires and of ballistic electron cavities is studied in the nonlinear transport regime. The energy dependence of the phasebreaking rate of nonequilibrium electrons in these structures is determined from the line shape of the suppression of weak localization due to voltage induced electronelectron interaction. The two terminal resistance of electron billiards without symmetry axis perpendicular to the current direction is found to be not symmetric upon current reversal in zero magnetic field. This effect appears to be related to ballistic weak localization inside the billiard.
The method of microwavedetection of the Shubnikovde Haas effect for the contactfree characterisation of transport properties of 2DEGs is explored using both magneticfield modulation and lightinduced carrier modulation. The methods are compared to magnetophotoluminescence (PL), cyclotron resonance (CR), optically detected CR, and to standard electrical measurements.
The effect of plasma dry etching of the surface of highmobility 2DEG samples on the properties of the 2DEG is studied. The PL and the transport properties of the 2DEG and the concentration of a paramagnetic surface defect created by the etching are found not to be correlated to each other.
The classical and the quantum mechanical dynamics of electrons in mesoscopic, open, triangular electron billiards is studied. The temperatureaveraged magnetoresistance can, using simulations, be explained by specific, classical electron trajectories, the relative importance of which is shown to depend on their Lyapunov stability. Quantum mechanical calculations reproduce observed conductance fluctuations which can be related to a specific electron orbit. Visualizations of the classical and the quantum mechanical electron density distribution inside the billiard are compared at various magnetic fields
The resistance of quasiballistic wires and of ballistic electron cavities is studied in the nonlinear transport regime. The energy dependence of the phasebreaking rate of nonequilibrium electrons in these structures is determined from the line shape of the suppression of weak localization due to voltage induced electronelectron interaction. The two terminal resistance of electron billiards without symmetry axis perpendicular to the current direction is found to be not symmetric upon current reversal in zero magnetic field. This effect appears to be related to ballistic weak localization inside the billiard.
Original language  English 

Qualification  Doctor 
Awarding Institution 

Supervisors/Advisors 

Award date  1997 Oct 3 
Publisher  
ISBN (Print)  9162826514 
Publication status  Published  1997 
Bibliographical note
Defence detailsDate: 19971003
Time: 10:15
Place: Hörsal B, Fysicum, Lund
External reviewer(s)
Name: Harmans, C J P M
Title: Assoc Prof
Affiliation: Delft University of Technology, The Netherlands

Subject classification (UKÄ)
 Condensed Matter Physics
Keywords
 quantum transport
 twodimensional electron gas
 contactfree characterisation
 ballistic transport
 mesoscopic
 electron billiard
 quantum dot
 electronelectron interaction
 nonlinear
 phase breaking
 Halvledarfysik
 Fysicumarkivet A:1997:Linke
 nonsymmetric conductio
 Semiconductory physics
 lowdimensional structures