Quick Search:
Prog. Theor. Phys. Supplement No.159 (2005) pp. 77-81
Finite-Field Ground State of an S = 1 Anisotropic Antiferromagnetic Chain
Takashi Tonegawa,1
Kouichi Okunishi,2
Tôru Sakai3 and
Makoto Kaburagi4
1Department of Mechanical Engineering, Fukui University of
Technology, Fukui 910-8505, Japan
2Department of Physics, Niigata University, Niigata 950-2181, Japan
3Department of Physics, Tohoku University, Sendai 980-8578, Japan
4Faculty of Cross-Cultural Studies, Kobe University, Kobe 657-8501, Japan
Abstract:
We investigate, using numerical methods, the finite-field ground-state
properties of an S = 1 anisotropic antiferromagnetic chain
described by the Hamiltonian
H = ∑\nolimitsℓSℓx Sℓ+1x
+ Sℓy Sℓ+1y + ΔSℓz Sℓ+1z
+ D ∑\nolimitsℓ (Sℓz)2
- H ∑\nolimitsℓSℓz.
It is found that the magnetization jump anomaly (a first-order
phase transition) appears in the ground-state
magnetization curve when Δ= 5.0 and
-1.50 \lesssimD \lesssim1.05; in a certain region of D, the jump starts
from a finite value of the magnetization m
per spin. We also find that the a second-order phase transition between
commensurate and incommensurate gapless phases takes place in the
finite-field ground state. The critical point of this transition as well as
the values of m at the onset and end of the magnetization jump is summarized
in the m versus D phase diagram.
URL :
http://ptp.ipap.jp/link?PTPS/159/77/
DOI : 10.1143/PTPS.159.77
References:
- L. Néel, Ann. de Phys. 5 (1936), 232.
-
T. Sakai and M. Takahashi, Phys. Rev. B 60 (1999), 7295[APS].
-
T. Sakai, Phys. Rev. B 58 (1998), 6268[APS].
-
W. Chen, K. Hida and B. C. Sanctuary, Phys. Rev. B 67 (2003), 104401[APS].
-
S. R. White, Phys. Rev. Lett. 69 (1992), 2863[APS];
Phys. Rev. B 48 (1993), 10345[APS].
- The case where Δ= 1 has already been discussed by
T. Tonegawa, Prog. Theor. Phys. Suppl. No. 46 (1970), 61[PTP].
-
J. C. Bonner and M. E. Fisher, Phys. Rev. 135 (1964), A640[APS].
-
H. J. Schulz, Phys. Rev. B 34 (1986), 6372[APS].
- See, for example, experimental papers on the magnetization plateau problem published in this issue and references quoted therein.
