We study the effects of a uniform magnetic field on the one-dimensional spin-orbital model in terms of effective field theories. Two regions are examined: one around the SU(4) point (Formula presented) and the other with (Formula presented) [see Eq. (1)]. We found that when (Formula presented) the spin and orbital correlation functions exhibit power-law decay with nonuniversal exponents. In the region with (Formula presented) the excitation spectrum has a gap but the structure of it changes at different range of the ratio (Formula presented) Furthermore, near the SU(4) point, the magnetic field exerts a great influence on the spectrum of the (Formula presented) sector. When the magnetic field is beyond some critical value, a quantum phase transition occurs. The different structure of the excitation spectrum results in distinct critical behavior of correlation functions around the SU(4) point and the region with (Formula presented) Especially, the exponents in the latter case are universal.
|Number of pages||10|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2000 Jan 1|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics