1991/01/01 by Subir Sachdev, N. Read · 2 citations
Physics and Astronomy · #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1142/s0217979291000158
published as International Journal of Modern Physics B 5, 219 (1991) · 38 pages, 5 figures; as published in the pre-cond-mat dark ages, of possible relevance to the experiments reported in cond-mat/0401621
crossref issued 1991/01/01 · crossref published 1991/01/01 · crossref published-print 1991/01/01 · arxiv created 2004/02/04 · crossref created 2004/11/25 · crossref published-online 2012/01/25 · arxiv updated 2014/12/25 · crossref deposited 2019/08/06 · crossref indexed 2026/08/05
A large N expansion technique, based on symplectic (Sp(N)) symmetry, for frustrated magnetic systems is studied. The phase diagram of a square lattice, spin S, quantum antiferromagnet with first, second and third neighbor antiferromagnetic coupling (the J 1 -J 2 -J 3 model) is determined in the large-N limit and consequences of fluctuations at finite N for the quantum disordered phases are discussed. In addition to phases with long range magnetic order, two classes of disordered phases are found: (i) states similar to those in unfrustrated systems with commensurate, collinear spin correlations, confinement of spinons, and spin-Peierls or valence-bond-solid order controlled by the value of 2S (mod 4) or 2S (mod 2) ; (ii) states with incommensurate, coplanar spin correlations, and unconfined bosonic spin-1/2 spinon excitations. The occurrence of “order from disorder” at large S is discussed. Neither chirally ordered nor spin nematic states are found. Initial results on superconductivity in the t—J model at N=∞ and zero temperature are also presented.