Magnetization dynamics in nanorings
(2015) FYSM31 20151Department of Physics
Mathematical Physics
 Abstract
 This thesis investigates numerically the out of equilibrium properties of quantum rings with magnetic impurities, using the periodic Anderson model (PAM). The model is a simple template for the discussion of the physics of regular arrays of rareearth impurities in metallic hosts. The system considered is a quantum ring consisting of up to six sites, each of whom are connected to an Anderson impurity site. The dynamical properties of this system are investigated numerically using exact diagonalization and Lanczos adapted time evolution. Two different schemes are used to perturb the system: a magnetic field piercing the ring and a local Zeeman interaction at one of the conduction sites. Comparisons are made with a ring without impurities,... (More)
 This thesis investigates numerically the out of equilibrium properties of quantum rings with magnetic impurities, using the periodic Anderson model (PAM). The model is a simple template for the discussion of the physics of regular arrays of rareearth impurities in metallic hosts. The system considered is a quantum ring consisting of up to six sites, each of whom are connected to an Anderson impurity site. The dynamical properties of this system are investigated numerically using exact diagonalization and Lanczos adapted time evolution. Two different schemes are used to perturb the system: a magnetic field piercing the ring and a local Zeeman interaction at one of the conduction sites. Comparisons are made with a ring without impurities, and it is shown that for very strong onsite interaction and/or very weak hybridization between the conduction sites and the impurity sites, the physics of a ring without impurities is recovered. Furthermore, a Doniachtype phase diagram in the presence of persistent currents, is provided where it is shown that the Kondo regime is reached for smaller values of the hybridization parameter when a magnetic field piercing the ring is present. The Doniach phase diagram is discussed in connection with persistent currents and entanglement. Preliminary results for the Zeeman field suggests a non trivial interplay between charge and spin currents, and RKKY and Kondolike couplings. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/studentpapers/record/7373510
 author
 Ydman, Simon ^{LU}
 supervisor

 Claudio Verdozzi ^{LU}
 organization
 course
 FYSM31 20151
 year
 2015
 type
 H2  Master's Degree (Two Years)
 subject
 keywords
 Kondo effect, quantum rings, doniach phase diagram, exact diagonalization
 language
 English
 id
 7373510
 date added to LUP
 20150624 22:15:08
 date last changed
 20150624 22:15:08
@misc{7373510, abstract = {This thesis investigates numerically the out of equilibrium properties of quantum rings with magnetic impurities, using the periodic Anderson model (PAM). The model is a simple template for the discussion of the physics of regular arrays of rareearth impurities in metallic hosts. The system considered is a quantum ring consisting of up to six sites, each of whom are connected to an Anderson impurity site. The dynamical properties of this system are investigated numerically using exact diagonalization and Lanczos adapted time evolution. Two different schemes are used to perturb the system: a magnetic field piercing the ring and a local Zeeman interaction at one of the conduction sites. Comparisons are made with a ring without impurities, and it is shown that for very strong onsite interaction and/or very weak hybridization between the conduction sites and the impurity sites, the physics of a ring without impurities is recovered. Furthermore, a Doniachtype phase diagram in the presence of persistent currents, is provided where it is shown that the Kondo regime is reached for smaller values of the hybridization parameter when a magnetic field piercing the ring is present. The Doniach phase diagram is discussed in connection with persistent currents and entanglement. Preliminary results for the Zeeman field suggests a non trivial interplay between charge and spin currents, and RKKY and Kondolike couplings.}, author = {Ydman, Simon}, keyword = {Kondo effect,quantum rings,doniach phase diagram,exact diagonalization}, language = {eng}, note = {Student Paper}, title = {Magnetization dynamics in nanorings}, year = {2015}, }