On Quantum Solitons in the Sawtooth Lattice

We study the sawtooth lattice of a coupled spin $1/2$ Heisenberg system, a variant of the railroad trestle lattice. The ground state of this system is two-fold degenerate with periodic boundary conditions and supports kink antikink excitations, which are distinct in this case, unlike the railroad trestle lattice. The resulting low temperature thermodynamics is compared with the recently discovered Delafossites $Y Cu O_{2.5} ~$.