Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 35: Correlated Electrons: Quantum-Critical Phenomena - Theory

TT 35.3: Vortrag

Dienstag, 8. März 2016, 14:30–14:45, H21

Spin trimers coupled in 2D — •Dominik Strassel and Sebastian Eggert — Department of Physics and Research Center Optimas, University Kaiserslautern, 67663 Kaiserslautern, Germany

We study linear clusters of three strongly coupled S = 1/2 spins (trimers), which are weakly connected in a two dimensional lattice. For this we use Stochastic Series Expansion Quantum Monte Carlo simulations of the Heisenberg model in a magnetic field. These systems show a magnetization plateau at 1/3 saturation, which is already known from strongly coupled three-leg ladders. In contrast to the frustrated triangular lattice which also shows a 1/3 plateau, our systems do not suffer from the infamous minus sign problem. With increasing coupling between the trimers the plateau vanishes and a bi-critical point can be identified. To understand this in more detail we develop an effective two boson model describing these systems analytically, which allows us to calculate the behavior near the bi-critical point (e.g. magnetization).