A. Matulis and N. Žurauskienė,
Semiconductor Physics Institute, Vilnius, Lithuania


Vilnius High Magnetic Field Centre (VMC) was established as a Joint institution between Semiconductor Physics Institute and Vilnius Gediminas Technical University. A compact system used for high pulsed magnetic field generation was designed. It enables to generate sinus-shaped pulses of 0.1-3 ms in duration and amplitudes up to 100 T in a multi-layered coil with cylindrically shaped cavity of 0.6 cm in diameter. The main research areas of VMC are design of high magnetic field generators, investigation of high magnetic field influence on condensed matter, and development of pulsed magnetic field sensors. In order to design the sensors based on manganites, thin nanometric size films of La-Sr-Mn-O grown on (001) NdGaO3 substrate using MOCVD method were investigated. The strong influence of the substrate on the resistance of the film and the strong in-plane anisotropy caused by film and substrate lattice constants mismatch was revealed.

Optically detected magnetic resonance (ODMR) measurements were performed on MBE-grown InAs/GaAs quantum dot (QD) structures:

  1. one layer of small-sized InAs/GaAs QDs and
  2. 5 layers of InAs QDs formed in the intrinsic region of p-i-n structure.
Optical detection of magnetic resonance was carried out via the change of the QD photoluminescence intensity under W-band (95 GHz) microwave excitation. Measurements were performed at a temperature of 1.8 K in an immersion cryostat and at 4.5 K in a flow cryostat. A cyclotron resonance of the electron in the two-dimensional InAs wetting layer, corresponding to an effective mass of 0.053m0, and hole spin transitions of the hole in the InAs QDs were observed.

The singular integral equation tehcnique was developed and applied to the Calculation of energy specturm of quantum antidots with sharp edges in magnetic field. Such nonostructures are perspective for the magnetotransport investigation and also as a model system for quantum chaos studies. As an example the magnetic edge mode spectrum of a impenetrable stripe was sudied. The most interesting feature of the obtained energy dependency on the magnetic field strength is the presence of some fractal plateaux related to the quantization of classical electron orbits composed of several Larmor circles.


  1. A. Matulis and Y. Levinson "Tunneling in Quantum Hall Systems", Materials Science Forum, Vols. 384-385, 3 (2002).

  2. A. Matulis, "Quantum Dots in a Strong Magnetic Field: Quasi-Classical Consideration", in book "Nano-Physics & Bio-Electronics: A New Odyssey", ed. by T. Chakraborty, F. M. Peeters, and U. Sivan, Elsevier, 2002, pp. 237-255.

  3. J. Reijnniers, A. Matulis, K. Chang, F. M. Peeters, and P. Vasilopoulos, "Confined Magnetic Guiding Orbit States", Europhys. Lett., Vol. 59 (5), 749 (2002).

  4. A. Matulis and T. Pyragiene, "Magnetic Edge States of Impenetrable Stripe", submitted to Phys. Rev. B.

  5. J. Novickij, S. Balevičius, N. Žurauskienė, P.Cimmperman, L.L. Altgilbers “Compact System for Pulsed High Magnetic Field Generation”, European Pulsed Power Symposium 2002, Saint Louis, France, October 22-24, 2002.

  6. G. Janssen, E. Goovaerts, A. Bouwen, D. Schoemaker, B. Partoens, N. Zurauskiene, P.M. Koenraad, J.H. Wolter, M. Hopkinson “Magnetic Properties of InAs/GaAs Quantum Dots Studied by Optically Detected Magnetic Resonance at 95 GHz”, CMD19-CMMP2002 Conference, 7-11 April 2002, Brighton (England).

Gerlinde Xander