Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 1: Correlated Electrons: Low-dimensional Systems - Models 1
TT 1.13: Vortrag
Montag, 26. März 2012, 12:45–13:00, H 0104
Magnetocaloric effect in Suzuki models. — Myroslava Topilko1, Oleg Derzhko1, and •Vadim Ohanyan2 — 1Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, L'viv-11, 79011, Ukraine — 2Department of Theoretical Physics, Yerevan State University, Al. Manoogian 1, 0025 Yerevan, Armenia
We consider the exactly solvable general spin-1/2 XX chain in an external (transverse) magnetic field with the multiple-spin(long range) interactions of the XZ...ZX+YZ...ZY and XZ...ZY-YZ...ZX types. The model can be mapped on the free spinless fermion system by means of Jordan-Wigner transformation. We focus on the magnetocaloric effect and entropic properties of the system. The simplest case of three-spin interaction which is equivalent to zigzag ladder is investigated in details. The plots of the adiabatic cooling rate are obtained. We examine the effect of coupling constants on the features of magnetocaloric effect. The main result is that tuning the parameters one can shift the position of magnetocaloric anomaly, but the magnitude of effect depends only on the properties of corresponding quantum phase transition. As the system under consideration possessed a quantum triple point, the maximal enhancement of magnetocaloric effect occurs at the quantum triple point.