Existence of a New Quantum Phase in Exactly Solvable Antiferromagnetic Ising-Heisenberg Models on Planar Lattices

In this work we deal with doubly decorated Ising-Heisenberg models on planar lattices. Applying the generalized decoration-iteration transformation we obtain exact results for the antiferromagnetic version of the model. The existence of a new quantum dimerized phase is predicted and its physical properties are studied and analyzed. Particular attention has been paid to the investigation of the phase boundaries, pair-correlation functions and specific heat. A possible application of the present work to some molecular magnets is also drawn.