Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2004-12-23
Lect. Notes Phys. 645, 85-153 (2004)
Physics
Condensed Matter
Strongly Correlated Electrons
These are the first 3 pages. The complete 72-page preprint version is available as PostScript (http://www.tu-bs.de/~honecker/p
Scientific paper
10.1007/BFb0119592
This is a review of ground-state features of the s=1/2 Heisenberg antiferromagnet on two-dimensional lattices. A central issue is the interplay of lattice topology (e.g. coordination number, non-equivalent nearest-neighbor bonds, geometric frustration) and quantum fluctuations and their impact on possible long-range order. This article presents a unified summary of all 11 two-dimensional uniform Archimedean lattices which include e.g. the square, triangular and kagome lattice. We find that the ground state of the spin-1/2 Heisenberg antiferromagnet is likely to be semi-classically ordered in most cases. However, the interplay of geometric frustration and quantum fluctuations gives rise to a quantum paramagnetic ground state without semi-classical long-range order on two lattices which are precisely those among the 11 uniform Archimedean lattices with a highly degenerate ground state in the classical limit. The first one is the famous kagome lattice where many low-lying singlet excitations are known to arise in the spin gap. The second lattice is called star lattice and has a clear gap to all excitations. Modification of certain bonds leads to quantum phase transitions which are also discussed briefly. Furthermore, we discuss the magnetization process of the Heisenberg antiferromagnet on the 11 Archimedean lattices, focusing on anomalies like plateaus and a magnetization jump just below the saturation field. As an illustration we discuss the two-dimensional Shastry-Sutherland model which is used to describe SrCu2(BO3)2.
Honecker Andreas
Richter Jadwiga
Schulenburg J/"org
No associations
LandOfFree
Quantum magnetism in two dimensions: From semi-classical Neel order to magnetic disorder does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Quantum magnetism in two dimensions: From semi-classical Neel order to magnetic disorder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quantum magnetism in two dimensions: From semi-classical Neel order to magnetic disorder will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-93748