Starting from the CPN-1 model description of the thermally disordered phase of the D=2 quantum antiferromagnet, we examine the interaction of the Schwinger-boson spin-1/2 mean-field excitations with the generated gauge (chirality) fluctuations in the framework of the 1/N expansion. This interaction dramatically suppresses the one-particle motion, but enhances the staggered static susceptibility. This means that the actual excitations in the system are represented by the collective spin-1 excitations, whereas the one-particle excitations disappear from the problem. We also show that massive fluctuations of the constraint field are significant for the susceptibility calculations. A connection with the problem of a particle in random magnetic field is discussed.
Physical Review B
- Pub Date:
- February 1994
- General theory and models of magnetic ordering;
- Spin waves;
- Condensed Matter
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