Absence of the long-range antiferromagnetic order in doped La2?x Sr x CuO4

Abstract

Based on a simple argument, it is shown that a small concentration of holes in a single band Hubbard Hamiltonian on a quadratic lattice with moderateU/t ratio is enough to destroy the long range antiferromagnetic order in the ground state. The particular emphasis is made on the role of large amplitude zero-point quantum spin fluctuations inherent in low-dimensional spin system with the small magnitude of spinS=1/2. The relevance to the highT c superconductivity materials La2−x Sr x CuO4 is discussed.