A standard two-dimensional (2D) XY model is well known to show a topological Berezinskii-Kosterlitz-Thouless (BKT) phase transition with the quasi-long-range-order (QLRO) BKT phase characterized by an algebraically decaying correlation function. It will be shown by spin-wave theory and Monte Carlo simulations that including higher-order terms can lead to dramatic changes in its critical behavior, including phase transition order or universality class and even the phase…
Zriedené feromagnetiká v teórii efektívneho poľa
prednášajúci: Andrej Bobák téma: Zriedené feromagnetiká v teórii efektívneho poľa charakter seminára: pracovný dátum: 25.10. čas: od 10:30 rozsah: cca. 45 min
Ising versus Potts criticality in a low-temperature magneto-thermodynamics of a frustrated spin-1/2 Heisenberg triangular bilayer
Low-temperature magnetization curves and thermodynamics of a frustrated spin-1/2 Heisenberg triangular bilayer with the antiferromagnetic intra-dimer interaction and either ferromagnetic or antiferromagnetic inter-dimer interaction are investigated in a highly frustrated parameter region, where localized many-magnon eigenstates provide the most dominant contribution to a magnetothermodynamics. Low-energy states of the highly frustrated spin-1/2 Heisenberg triangular bilayer can be accordingly found from a mapping correspondence with the effective…