Breakdown of the conventional spin-wave dynamics and its double-constraint modification in the spin-$\frac{1}{2}$ triangular-prism Heisenberg antiferromagnet

Shoji Yamamoto, Jun Ohara

Spontaneous magnon decays in an $S=\frac{1}{2}$ Heisenberg antiferromagnet on the equilateral triangular prism are investigated in terms of modified magnon Green's functions. In on…