Ground State of Quantum Spin Systems on the Triangular Lattice

Abstract

The ground states of quantum spin systems with spin 1 / 2 are investigated on the triangular lattice by numerically diagonalizing finite size systems ( N ≦27). In the ferromagnetic and antiferromagnetic X Y models the correlation functions are found to decay by power laws. The antiferromagnetic Heisenberg model is likely to be paramagnetic in the ground state. Thus the classical long-range order is destroyed by quantum effects in all of the models we studied.