Optimization of ionic configurations in battery materials by quantum annealing

Energy materials with disorder in site occupation are challenging forcomputational studies due to an exponential scaling of the configuration space.We herein present a grand-canonical optimization method that enables the use ofquantum annealing (QA) for sampling the ionic ground state. The method relieson a Legendre transformation of the Coulomb energy cost function that stronglyreduces the effective coupling strengths of the fully connected problem, whichis essential for effectiveness of QA. The approach is expected to be applicableto a variety of materials optimization problems.