| CZECH NANO TEAM | Physics of Nanostructures and Nanotechnologies

Ludvík Smrčka

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Group subject:

MBE AIIIBV nanostructures and diluted magnetic semiconductors

Name and Curriculum vitae of contact person:

Ludvík Smrčka (Ing., DrSc.)

Affiliation:

Institute of Physics, Academy of Sciences of the Czech Republic

Position - Head of Department of Physics of Surfaces and Interfaces

Fields of scientific activity:

• Theory of solid state physics, electronic structure of metals and semiconductors, low-dimensional semiconductor structures.
• Design of quantum wells and double quantum wells, numerical modeling of their electronic structure.
• Theoretical research of cyclotron resonance and luminescence in semiconductor nanostructures subject to magnetic fields.
• Theoretical and experimental research of dc magnetotransport of two-dimensional electron single-layers and bi-layers at low temperatures and in strong magnetic fields.
• The supervisor of 6 successful MSc theses and supervisor/consultant of 6 PhD theses.

Publications:

Author or co-author of more than 65 papers in international scientific journals to which more than 550 references appeared in the literature. Amongst these there are joint papers with the Michigan State University, SUNY at Buffalo, High Pressure Research Center in Warsaw, Inst. Metrol. Serv. in Moscow, Institute of Low Temp Phys.& Eng. , Kharkov, University of Munich, Princeton University, Indiana State University in Bloomington, Osaka University, University Erlangen-Nurnberg, NHMFL v Tallahassee, Bell Labs v Murray Hill, Columbia University, GHMFL in Grenoble, Walter Schottky Institute, Garching. There are two Nobel Prize winners among the co-authors. 10 invited talks presented at international conferences.

Selected study stays abroad:

• In 1973 6 month's with Prof. F.J. Blatt at Michigan State University, U.S.A
• In 1985 invited by Prof. Akira Isihara for 3 month's stay at State University of New York , Buffalo, U.S.A
• From 1996 till present a series of 12 week stays at Grenoble High Magnetic Field Laboratory, devoted to low-temperature magnetotransport experiments in strong magnetic fields up to 20-30 T.

Selected solved projects :
• 1992 - 1994 Educational grant of the Ministry of Education CR No. V091 ''Center of material research and education''
• 1999 - 2001 Czech-French project Barrande 99011 ''Magnetotransport in semiconductor structures''
• 2003 - Czech-French project Barrande 2003-13 ''Superlattices and multi-wells in tilted magnetic fields''

Selected related publications from last 5 years:

• K. Výborný, L. Smrčka, R. A. Deutschmann: Magnetoresistance calculations for a two-dimensional electron gas with unilateral short-period strong modulation, Phys. Rev. B 66, 20538 (2002)

• J. Kolorenč, L. Smrčka, P. Středa: Interlayer Hall effect in double quantum wells subject to in-plane magnetic fields , Phys. Rev. B 66, 05301 (2002)

• O. N. Makarovskii, L. Smrčka, P. Vašek , T. Jungwirth, M. Cukr, L. Jansen: Magnetoresistance and electronic structure of asymmetric GaAs/Al0.3Ga0.7As double quantum wells in an in-plane or tilted magnetic field , Phys. Rev. B 62, 10908 (2000)

• W. Pan W., Jungwirth T., H.L. Stormer , D.C. Tsui , A.H. Mac Donald, S.M. Girvin , L. Smrčka, L.N. Pfeiffer, K.W. Baldwin , K.W. West : Reorientation of anisotropy in a square well quantum Hall sample , Phys. Rev. Lett. 85, 3257 (2000)

• J.Soubusta, R. Grill, P. Hlídek, M. Zvára, L. Smrčka, S. Malzev , W. Geisselbrecht, G.H. Dohler: Excitonic photoluminescence in symmetric coupled double quantum wells subject to an external electric field, Phys. Rev. B 60, 7740 (1999)

Group members:

L. Smrčka, M. Cukr, V. Novák Z. Výborný, V. Jurka, P. Svoboda, P. Vašek, T. Jungwirth, P. Středa, J. Kučera

Main Research Subjects:

The first subject of molecular beam epitaxy (MBE) group is preparation of AIIIBV planar nanostructures: heterostructures, multiple quantum wells and superlattices which host two dimensional electron/hole layers, either independent or tunnel coupled. The second subject is the growth of AIIIBV layers doped with Mn with the aim to prepare diluted magnetic semiconductors with the critical temperature close to the room temperature and finally to prepare planar semiconductor nanostructures which will combine non-magnetic and ferromagnetic semiconductors.
The optical lithography will be used to shape various samples appropriate for further experimental investigations. Among them are first of all measurements of magnetization and electron transport properties in the wide range of temperatures starting from milikelvins to room temperatures and in magnetic fields up to 30T. The very high field measurements will be realized in Grenoble High Magnetic Field Laboratory.
The development of recent theoretical research of the electronic structure of ferromagnetic semiconductors and of the spin-polarized transport will continue to allow for comparison between theory and experiment, to advance understanding of ferromagnetism in diluted magnetic semiconductors, particularly (III,Mn)V materials, and to contribute to new emerging field of spintronics.

Selected Specific Equipment:

Two molecular beam epitaxy machines (Kryovak, which is in use since 1989, and recently installed Gen II from Veeco company ) are the main tools for growth of semiconductor nanostructures. A special chamber connected to Omicron AFM/STM variable temperature UHV system, serves for cleaving the samples under high vacuum , and for cross-sectional STM investigation of their structure with the atomic resolution.
Clean rooms are fully equipped for pattering the samples, preparing the back- and front- gates and ohmic contacts to the conducting electron/hole layers in the structures.
Low temperature laboratory equipped with 14 Tesla superconducting magnet enable us to realize low-noise measurements of magneto-resistance, Hall effect and termo-galvano-magnetic properties from 0.3 K to the room temperatures.

Additional recent selected publications by group members:

• T. Jungwirth, J. Mašek, Jairo Sinova, A. H. MacDonald: Ferromagnetic transition temperature enhancement in(Ga,Mn)As semiconductors by carbon codoping, Phys. Rev. B 68, 161202(1-4) (2003)

• P. Středa, P.Šeba: Antisymmetric spin filtering in one-dimensional electron systems with uniform spin-orbit coupling,, Phys. Rev. Lett. 90, 256601(1-4) (2003)

• T. Jungwirth, Jairo Sinova, J. Kučera, A. H. MacDonald: Theoretical models of ferromagnetic III-V semiconductors, Curr. Appl. Phys. 3, 461-464 (2003)

• T. Jungwirth, Jairo Sinova, K. Y. Wang, K. W. Edmonds, R. P. Campion, B. L. Gallagher, C. T. Foxon, Qian Niu, A. H. MacDonald: Dc-transport properties of ferromagnetic (Ga,Mn)As semiconductors, Appl. Phys. Lett. 83, 320-322 (2003)

• Jairo Sinova, T. Jungwirth, J. Kučera, A. H. MacDonald: Infrared magneto-optical properties of (III,Mn)V ferromagnetic semiconductors, Phys. Rev. B 67, 235203(1-12) (2003)

• E. H. Rezayi, T. Jungwirth, A. H. MacDonald, F. D. M. Haldane: Exact diagonalization study of domain structure in integer filling factor quantum Hall ferromagnets, Phys. Rev. B 67 , 201305 (1-4) (2003)

• S.-R. Eric Yang, Jairo Sinova, T. Jungwirth, Y. P. Shim, A. H. MacDonald: Non-Drude optical conductivity of (III,Mn)V ferromagnetic semiconductors, Phys. Rev. B 67, 045205(1-7) (2003)

• P. Šeba, P. Exner, K. N. Pichugin, A. Vyhnal, P. Středa: Two-Component Interference Effect: Model of a Spin-Polarized Transport, Phys. Rev. Lett. 86, 1598(1-4), (2001)