%0 Journal Article %J Nano Letters %D In Press %T Two-electron-spin ratchets as a platform for microwave-free dynamic nuclear polarization of arbitrary material targets %A P.R. Zangara %A J. Henshaw %A D. Pagliero %A A. Ajoy %A J. Reimer %A A. Pines %A C. Meriles %B Nano Letters %G eng