%0 Journal Article %T Magnetic field-induced insulator-semimetal transition in a pyrochlore Nd2Ir2O7 %A K. Ueda %A J. Fujioka %A B. -J. Yang %A J. Shiogai %A A. Tsukazaki %A S. Nakamura %A S. Awaji %A N. Nagaosa %A Y. Tokura %J Physics %D 2015 %I arXiv %R 10.1103/PhysRevLett.115.056402 %X We have investigated magneto-transport properties in a single crystal of pyrochore-type Nd2Ir2O7. The metallic conduction is observed on the antiferromagnetic domain walls of the all-in all-out type Ir-5d moment ordered insulating bulk state, that can be finely controlled by external magnetic field along [111]. On the other hand, an applied field along [001] induces the bulk phase transition from insulator to semimetal as a consequence of the ?eld-induced modification of Nd-4f and Ir-5d moment con?gurations. A theoretical calculation consistently describing the experimentally observed features suggests a variety of exotic topological states as functions of electron correlation and Ir-5d moment orders which can be finely tuned by choice of rare-earth ion and by magnetic field, respectively. %U http://arxiv.org/abs/1506.07336v1