Abstract
The Green's function formalism proposed by Kondo and Yamaji for low-dimensional spin systems with S=1/2 has been extended to the cases of S>1/2. We apply this formalism to the study of one- and two-dimensional Heisenberg ferromagnets over the whole temperature range. It is shown that our theory can reproduce the correct results obtained by the high-temperature expansion method. On the other hand, the results at low temperatures are similar to those of the modified spin-wave theory, which is considered to predict the low-temperature properties of such systems rather correctly. The gross behaviors of the calculated thermodynamic quantities of ferromagnetic Heisenberg chains agree with those obtained by the exact diagonalization method.
| Original language | English |
|---|---|
| Pages (from-to) | 1539-1547 |
| Number of pages | 9 |
| Journal | journal of the physical society of japan |
| Volume | 63 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1994 Jan 1 |
| Externally published | Yes |
Keywords
- Green's function
- Heisenberg ferromagnet
- Kondo-Yamaji theory
- arbitrary magnitudes of spin
- one dimension
- two dimensions
- whole temperature range
ASJC Scopus subject areas
- Physics and Astronomy(all)