  Quantum correlations including entanglement and quantum discord has drawn
much attention in characterizing quantum phase transitions. Quantum deficit
originates in questions regarding work extraction from quantum systems coupled
to a heat bath [Phys. Rev. Lett. 89, 180402 (2002)]. It links quantum
thermodynamics with quantum correlations and provides a new standpoint for
understanding quantum non-locality. In this paper, we evaluate the one-way
deficit of two adjacent spins in the bulk for the XX model. In the
thermodynamic limit, the XX model undergoes a first order transition from fully
polarized to a critical phase with quasi-long-range order with decrease of
quantum parameter. We find that the one-way deficit becomes nonzero after the
critical point. Therefore, the one-way deficit characterizes the quantum phase
transition in the XX model.
