Correlation effects and disorder in mesoscopic and strongly correlated systems  Page description

Help  Print 
Back »
 

Details of project

  
Identifier
46303
Type K
Principal investigator Zaránd, Gergely Attila
Title in Hungarian Korrelációk és rendezetlenség mezoszkópikus és erősen korrelált rendszerekben
Title in English Correlation effects and disorder in mesoscopic and strongly correlated systems
Panel Physics 1
Department or equivalent Department of Theoretical Physics (Budapest University of Technology and Economics)
Participants Borda, László
Újsághy, Orsolya
Varga, Imre
Starting date 2004-01-01
Closing date 2008-06-30
Funding (in million HUF) 8.425
FTE (full time equivalent) 0.00
state closed project





 

Final report

  
Results in Hungarian
Kutatásaink egy részében mezoszkópikus rendszerek viselkedését tanulmányoztunk, ahol mind az elektron-elektron kölcsönhatás, mind pedig a rendezetlenség ill. a rendszerspecifikus apró részletek fontos szerepet játszanak esetükben. A kutatás célja ezeknek a tulajdonságoknak együttes tanulmányozása volt. Egyik fő célunk a szennyezések ill. a koherenciát erősen befolyásoló inelasztikus folyamatok megértése volt. Másfelől kvantum pöttyökben fellépő egzotikus korrelált állapotokat vizsgáltunk kutatásaink során. A projekt másik fő célkitűzéseként rendezetlen rendszerekbeli korrelációs effektusokat, a fém-szigetelő fázisátalakulás számos vonását, és korreláció-indukálta kvantum fázisátalakulásokat tanulmányoztunk numerikus és analítikus módszerekkel. Itt kutatásaink elsősorban a félvezető rendszerekbeli Mott-Anderson átalakulásra ill. a mágnesség és a rendezetlenség mágneses félvezetőkbeli összefüggésének tanulmányozására irányultak. Az OTKA projekthez kapcsolódóan mintegy 44 publikációnk jelent meg, közülük 12 a Physical Review Letters hasábjain 20 pedig a Physical Review B-ben. Ezekre a közleményekre már eddig is több mint 200 független hivatkozás érkezett. A résztvevő kutatók mintegy félszáz meghívott előadást tartottak nemzetközi konferenciákon ill. külföldi kutatási intézményekben. A kutatáshoz kapcsolódóan öt diplomamunka, egy Ph.D. értekezés, és egy akadémiai doktori disszertáció született.
Results in English
Part of our research focused on the study of mesoscopic systems. In these small structures the electron-electron interaction as well as disorder and sample-specific details play an essential role. Our main goal was to study these effects and their interplay. One of our main goals was to understand how impurities affect inelastic processes and lead to the destruction of coherence. On the other hand, we studied exotic correlated states which form in mesoscopic quantum dot structures. The other main objective of this research project was to study disordered systems, several aspects of the metal-insulator transition, and correlation-induced quantum phase transitions using a variety of analytical and numerical methods. This part of the project focused mostly on the Mott-Anderson transition in semiconductor systems and the interplay of magnetism and localization effects in ferromagnetic semiconductors. Related to the project, a total of 44 publications appeared, 12 of them in the Physical Review Letters, and another 20 in the Physical Review B. So far we received over 200 independent citations for these publications. The participants of the project gave over 50 invited talks on international conferences and schools, and in international research institutions. Five diploma thesis, a Ph.D. thesis and a (D.Sc., i.e. Doctor of the Academy of Sciences) dissertation have been written and defended as part of this research project.
Full text http://real.mtak.hu/1377/
Decision
Yes





 

List of publications

  
O. Újsághy and A. Zawadowski: Kondo effect on mesoscopic scale, J. Phys. Soc. Japan 74, 80, 2004
L. Borda, F. Guinea: Assisted hopping and interaction effects in impurity models, Phys. Rev. B 70, 125118, 2004
G. A. Fiete, G. Zarand, B. Janko, P. Redlinski, C. P. Moca: Positional Disorder, Spin-Orbit Coupling and Frustration in GaMnAs, Phys. Rev. B 71, 115202, 2005
V. Filinov, P. Thomas, M. Bonitz, V. Fortov, I. Varga, and T. Meier: Wigner approach to quantum dynamics simulations of the interacting carriers in disordered systems, Physica Status Solidi (b) 241 40-46, 2004
C. Aulbach, A. Wobst, G-L. Ingold, P. Hänggi and I. Varga: Phase space visualisation of a metal-insulator transition, New Journal of Physics 6, 70, 2004
M. Garst, P. Wölfle, L. Borda, J. von Delft, L. I. Glazman: Energy-resolved inelastic electron scattering off a magnetic impurity, Phys. Rev. B 72, 205125, 2005
L. Borda, G. Zaránd, and P. Simon: Dissipation-induced quantum phase transition in a quantum box, Phys. Rev. B 72, 155311, 2005
G. A. Fiete, G. Zaránd, K. Damle, and C. P. Moca: Disorder, spin-orbit, and interaction effects in dilute Ga1-x Mnx As, Phys. Rev. B 72, 045212, 2005
E. Novais, A. H. Castro Neto, L. Borda, I. Affleck, and G. Zarand: Frustration of decoherence in open quantum systems, Phys. Rev. B 72, 014417, 2005
O. Újsághy, A. Jakovác, and A. Zawadowski: Energy relaxation due to magnetic impurities in mesoscopic wires: Logarithmic approach, Phys. Rev. B 72, 205119, 2005
M. Pustilnik, L. Borda: Phase transition, spin-charge separation, and spin filtering in a quantum dot, Phys. Rev. B 73, 201301(R), 2006
J. A. Mendez-Bermudez, I. Varga: Scattering at the Anderson transition: Power-law banded random matrix model, Physical Review B 74, 125114 (2006), 2006
L. Borda: Kondo screening cloud in a one dimensional wire: Numerical renormalization group study, Phys. Rev. B 75, 041307(R), 2007
Rapp A, Zarand G: Dynamical correlations and quantum phase transition in the quantum Potts model, Phys. Rev. B 74, 014433 (2006), 2006
Kaul RK, Zarand G, Chandrasekharan S, et al:: Spectroscopy of the Kondo problem in a box, Phys. Rev. Lett. 96, 176802 (2006), 2006
Zarand G: Orbital fluctuations and strong correlations in quantum dots, Phil. Mag. 86, 2043-2072 (2006), 2006
Szunyogh L, Zarand G, Gallego S, et al: Effect of spin-orbit interaction on a magnetic impurity in the vicinity of a surface, Phys. Rev. Lett. 96, 067204 (2006), 2006
G. Zaránd: Quantum Impurity Problems, MTA Doktora Disszertáció, 2006
László Borda, Lars Fritz, Natan Andrei, and Gergely Zaránd: Theory of inelastic scattering from quantum impurities, Physical Review B 75, 235112, 2007
A. I. Tóth, L. Borda, J. von Delft, and G. Zaránd: Dynamical conductance in the two-channel Kondo regime of a double dot system, Phys. Rev. B 76, 155318, 2007
Pablo San-Jose, Burkhard Scharfenberger, Gerd Schön, Alexander Shnirman, and Gergely Zarand: Geometric phases in semiconductor spin qubits: Manipulations and decoherence, Phys. Rev. B 77, 045305, 2008
Chung-Hou Chung, Gergely Zarand, and Peter Wölfle: Two-stage Kondo effect in side-coupled quantum dots: Renormalized perturbative scaling theory and numerical renormalization group analysis, Phys. Rev. B 77, 035120, 2008
B. Horváth, B. Lazarovits, O. Sauret, and G. Zaránd: Failure of the mean-field approach in the out-of-equilibrium Anderson model, Phys. Rev. B 77, 113108, 2008
Ákos Rapp, Walter Hofstetter, and Gergely Zaránd: Trionic phase of ultracold fermions in an optical lattice: A variational study, Phys. Rev. B 77, 144520, 2008
Cătălin Paşcu Moca, Eugene Demler, Boldizsár Jankó, and Gergely Zaránd: Spin-resolved spectra of Shiba multiplets from Mn impurities in MgB2, Phys. Rev. B 77, 174516, 2008
G. Zarand and L. Borda: Inelastic scattering from quantum impurities, Physica E 40, 5, 2007
P. San-Jose, G. Schon, A. Shnirman, and G. Zarand: Spin dephasing due to a random Berry phase, Physica E 40, 76, 2007
P. Bozsoki, M. Kira, W. Hoyer, T. Meier, I. Varga, P. Thomas, and S.W. Koch: Microscopic modelling of photoluminescence of strongly disordered semiconductors, Journal of Luminescence, 124, 99-112, 2007
C. Kozmutza, F. Bartha, L. Udvardi, and I. Varga: Study of the effect of metal ions on hydroxyl-containing molecules, Int. J. of Quantum Chemistry, 107 (14), 2730-2740, 2007
P. Bozsoki, W. Hoyer, M. Kira, I. Varga, P. Thomas, S.W. Koch, and H. Schomerus: Analytical analysis of single-photon correlations emitted by disordered semiconductor heterostructures, Journal of Material Science: Materials in Electronics¸ online, 2007
I. Varga and J.A. Mendez-Bermudez: Entanglement in disordered systems at criticality, Physica Status Solidi (c) 5, 867-870, 2008
P Bozsoki, I. Varga, and H. Schomerus: Electron-electron relaxation in disordered interacting systems, Physica Status Solidi (c) 5, 699-702, 2008
L. Borda, K. Vladár, A. Zawadowski: "Theory of a resonant level coupled to several conduction electron channels in equilibrium and out-of-equilibrium", Phys. Rev. B 75, 125107, 2007
Pankaj Mehta, Natan Andrei, P. Coleman, L. Borda, and Gergely Zarand: Regular and singular Fermi-liquid fixed points in quantum impurity models, Phys. Rev. B 72, 014430, 2005
G. Zarand, L. Borda, J. von Delft, and N. Andrei: Theory of Inelastic Scattering from Magnetic Impurities, Phys. Rev. Lett. 93, 107204, 2004
O. Újsághy, A. Jakovác, and A. Zawadowski: Role of surface anisotropy for magnetic impurities in electron dephasing and energy relaxation and their size effect, Phys. Rev. Lett. 93, 256805, 2004
B. Lazarovits, P. Simon, G. Zaránd, and L. Szunyogh: Exotic Kondo Effect from Magnetic Trimers, Phys. Rev. Lett. 95, 077202, 2005
G. Zaránd, C. P. Moca, and B. Jankó: Scaling Theory of Magnetoresistance in Disordered Local Moment Ferromagnets, Phys. Rev. Lett. 94, 247202, 2005
P. Bozsoki, P. Thomas, M. Kira, W. Hoyer, T. Meier, S.W. Koch, K. Maschke,: Characterization of Disordered Semiconductors via Single-Photon Interferometry, Phys. Rev. Lett. 97, 227402 (2006), 2006
San-Jose P, Zarand G, Shnirman A, et al.: Geometrical spin dephasing in quantum dots, Phys. Rev. Lett. 97, 076803 (2006), 2006
Zarand G, Chung CH, Simon P, and M. Vojta: Quantum criticality in a double-quantum-dot system, Phys. Rev. Lett. 97, 166802 (2006), 2006
Rech J, Coleman P, Zarand G, et al.: Schwinger boson approach to the fully screened Kondo model, Phys Rev. Lett. 96, 016601, 2006
A. Rapp, G. Zarand, C. Honerkamp, and W. Hofstetter: Color superfluidity and "Baryon" formation in ultracold fermions, Physical Review Letters, 2007
Tamara S. Nunner, Gergely Zaránd, and Felix von Oppen: Anomalous Hall Effect in a Two Dimensional Electron Gas with Magnetic Impurities, Phys. Rev. Lett. 100, 236602, 2008



Back »