2007/04/30 by Ozan S. Sariyer, Ozan S. Sarıyer, A. Nihat Berker +1 · 10 citations
Physics and Astronomy · #Anisotropy #Antiferromagnetism #Condensed matter physics #Ferromagnetism #Heisenberg model #Ising model #Physics #Physics of Superconductivity and Magnetism #Quantum many-body systems #Quantum mechanics #Spin (aerodynamics) #Spin wave #Theoretical and Computational Physics #Thermodynamics #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevb.77.134413
published in Physical Review B 77(13) (American Physical Society) · New results added to text and figures. 12 pages, 18 figures, 3 tables. Published version
openalex publication_date 2008/04/04 · arxiv created 2008/04/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The anisotropic XXZ spin-(1)/(2) Heisenberg chain is studied using renormalization-group theory. The specific heats and nearest-neighbor spin-spin correlations are calculated throughout the entire temperature and anisotropy ranges in both ferromagnetic and antiferromagnetic regions, obtaining a global description and quantitative results. We obtain, for all anisotropies, the antiferromagnetic spin-liquid spin-wave velocity and the Ising-like ferromagnetic excitation spectrum gap, exhibiting the spin-wave to spinon crossover. A number of characteristics of purely quantum nature are found: The in-plane interaction sixsjx+siysjy induces an antiferromagnetic correlation in the out-of-plane siz component, at higher temperatures in the antiferromagnetic XXZ chain, dominantly at low temperatures in the ferromagnetic XXZ chain, and, in-between, at all temperatures in the XY chain. We find that the converse effect also occurs in the antiferromagnetic XXZ chain: an antiferromagnetic sizsjz interaction induces a correlation in the sixy component. As another purely quantum effect, (i) in the antiferromagnet, the value of the specific heat peak is insensitive to anisotropy and the temperature of the specific heat peak decreases from the isotropic (Heisenberg) with introduction of either type (Ising or XY) of anisotropy; and (ii) in complete contrast, in the ferromagnet, the value and temperature of the specific heat peak increase with either type of anisotropy.