Formation of orbital molecules on a pyrochlore lattice induced by A-O\n bond covalency
Le résumé fourni par la source
The pyrochlore ruthenate In$_2$Ru$_2$O$_7$ displays a subtle competition\nbetween spin-orbital entanglement and molecular orbital formation. At room\ntemperature, a spin-orbit-entangled singlet state was identified. With\ndecreasing temperature, In$_2$Ru$_2$O$_7$ undergoes multiple structural\ntransitions and eventually forms a nonmagnetic ground state with semi-isolated\nRu$_2$O units on the pyrochlore lattice. The dominant hopping through the\nRu-O-Ru linkage leads to molecular orbital formation within the Ru$_2$O units.\nThis molecular orbital formation is unique in that it involves the O$^{2-}$\nanions, unlike the transition-metal dimers observed in systems with\nedge-sharing octahedra. We argue that the covalent character of In-O bonds\nplays a pivotal role in the structural transitions and molecular orbital\nformation and such bonding character of "$A$-site" ions is an important\ningredient for electronic phase competition in complex transition metal oxides.\n
Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.