Randomness-Induced Quantum Spin Liquid Behavior in the s =1 /2 Random-Bond Heisenberg Antiferromagnet on the Pyrochlore Lattice

We investigate the zero- and finite-temperature properties of the random-bond s =1 /2 Heisenberg antiferromagnet on the pyrochlore lattice by the exact diagonalization and the Hams-de Raedt methods. We find that the randomness induces the gapless quantum spin liquid (QSL) state, the random-singlet state. Implications to recent experiments on the mixed-anion pyrochlore-lattice antiferromagnet Lu₂Mo₂O₅N₂ exhibiting gapless QSL behaviors are discussed.