Formation of orbital molecules on a pyrochlore lattice induced by A-O\n bond covalency

2021/11/09 by Aleksandra Krajewska, A. N. Yaresko, Krajewska, A. +43
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Nuclear materials and radiation effects #Strongly Correlated Electrons (cond-mat.str-el)

paper · pdf · doi:10.48550/arxiv.2111.05057

openalex publication_date 2021/11/09 · openalex created_date 2022/05/05 · openalex updated_date 2026/07/28

Abstract

The pyrochlore ruthenate In₂Ru₂O₇ 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, In₂Ru₂O₇ undergoes multiple structural\ntransitions and eventually forms a nonmagnetic ground state with semi-isolated\nRu₂O units on the pyrochlore lattice. The dominant hopping through the\nRu-O-Ru linkage leads to molecular orbital formation within the Ru₂O 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

Citations

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