Modified spin-wave theory with ordering vector optimization: spatially anisotropic triangular lattice and J(1)J(2)J(3) model with Heisenberg interactions

Autor(en)

Philipp Hauke, Tommaso Roscilde, Valentin Murg, J. Ignacio Cirac, Roman Schmied

Abstrakt

We study the ground-state phases of the S = 1/2 Heisenberg quantum antiferromagnet on the spatially anisotropic triangular lattice (SATL) and on the square lattice with up to next-next-nearest-neighbor coupling (the J(1)J(2)J(3) model), making use of Takahashi's modified spin-wave (MSW) theory supplemented by ordering vector optimization. We compare the MSW results with exact diagonalization and projected-entangled-pair-states calculations, demonstrating their qualitative and quantitative reliability. We find that the MSW theory correctly accounts for strong quantum effects on the ordering vector of the magnetic phases of the models under investigation: in particular, collinear magnetic order is promoted at the expense of non-collinear (spiral) order, and several spiral states that are stable at the classical level disappear from the quantum phase diagram. Moreover, collinear states and non-collinear ones are never connected continuously, but they are separated by parameter regions in which the MSW theory breaks down, signaling the possible appearance of a nonmagnetic ground state. In the case of the SATL, a large breakdown region appears also for weak couplings between the chains composing the lattice, suggesting the possible occurrence of a large non-magnetic region continuously connected with the spin-liquid state of the uncoupled chains. This shows that the MSW theory is-despite its apparent simplicity-a versatile tool for finding candidate regions in the case of spin-liquid phases, which are among prime targets for relevant quantum simulations

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

The Institute of Photonic Sciences, École normale supérieure de Lyon (ENS Lyon), Max-Planck-Institut für Quantenoptik, Universität Basel

Journal

New Journal of Physics

Band

13

Anzahl der Seiten

29

ISSN

1367-2630

DOI

https://doi.org/10.1088/1367-2630/13/7/075017

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/2930c326-dd9c-4082-be4a-9ddb8bfe2ee8