Dual Orbital Degeneracy Lifting In A Strongly Correlated Electron System

The local structure of NaTiSi2O6 is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the transition. The analysis unravels that, on warming, the dimers evolve into a short range orbital degeneracy lifted (ODL) state of dual orbital character, persisting up to at least 490 K. The ODL state is correlated over the length scale spanning similar to 6 sites of the Ti zigzag chains. Results imply that the ODL phenomenology extends to strongly correlated electron systems.