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 XY 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.