Specific heat of spin-one-half frustrated Heisenberg ladder

The specific heat of S = 1/2 frustrated Heisenberg antiferromagnetic spin l adder is investigated by means of a modified spin-wave theory. It is found that at low temperatures the specific heat shows a round peak, and decays e xponentially below the peak temperature. The maximum of the specific heat d ecreases with increasing the lung-couplings, while it increases with increa sing the diagonal couplings. The peak temperature moves to lower temperatur es when the rung-coupling is increased, while it shifts to higher temperatu res when the diagonal coupling is increased. Our observation is expected to be confirmed experimentally. (C) 2001 Elsevier Science B.V. All rights res erved.