Impact of iso-structural template layer on stabilizing pyrochlore Bi${}_2$Rh${}_2$O${}_7$

Abstract

We present an epitaxial stabilization of pyrochlore Bi${}_2$Rh${}_2$O${}_7$ on Y-stabilized ZrO${}_2$ (YSZ) (111) substrate by inserting a pyrochlore Eu${}_2$Ti${}_2$O${}_7$ template layer, otherwise Bi-based layered structures being formed directly on YSZ (111) substrate. This result reveals that "iso-structural crystal phase" plays an important role in the interfacial phase control. The Bi${}_2$Rh${}_2$O${}_7$ film exhibits $p$-type electrical conduction with the lowest longitudinal resistivity (${\rho }_{\mathrm{xx}}$) among the reported Rh pyrochlore oxides. Such parameters as ${\rho }_{\mathrm{xx}}$, carrier density, and mobility show almost no temperature dependence in the measured range of 2$-$300 K, indicating Bi${}_2$Rh${}_2$O${}_7$ as one of the rare examples of conducting pyrochlore oxides.