Pyrochlore oxides are fascinating systems where strong, multi-orbital correlations in concert with geometrical frustration give rise to unanticipated physical properties. The detailed mechanism of the insulator-metal transitions (IMT) underpinning these phenomena is, however, ill-understood in general. Motivated thereby, we study the IMT in the pyrochlore Hg2Ru2O7 using LDA+DMFT. In contrast to the well-known examples of Mott transitions in TMO, we show that, in the negative charge-transfer situation characteristic of \hg, self-doping plays a crucial role in the emergence of an orbital-selective IMT. We argue that this mechanism has broader relevance to other correlated pyrochlore oxides.
@article{arxiv.0901.4658,
title = {Self-Doping Induced Orbital-Selective Mott Transition in Hg2Ru2O7},
author = {L. Craco and M. S. Laad and S. Leoni and H. Rosner},
journal= {arXiv preprint arXiv:0901.4658},
year = {2009}
}