Optical study of MgTi${}_2$O${}_4$: Evidence for an orbital-Peierls state

Abstract

Dimension reduction due to the orbital ordering has recently been proposed to explain the exotic charge, magnetic and structural transitions in some three-dimensional (3D) transitional metal oxides. We present optical measurement on a spinel compound MgTi${}_2$O${}_4$ which undergoes a sharp metal-insulator transition at 240 K, and show that the spectral change across the transition can be well understood from the proposed picture of 1D Peierls transition driven by the ordering of $d_{yz}$ and $d_{zx}$ orbitals. We further elaborate that the orbital-driven instability picture applies also very well to the optical data of another spinel CuIr${}_2$S${}_4$ reported earlier.

5 pages, 6 figures, to be published in Phys. Rev. B

References in corpus (3)

• Orbital-assisted metal-insulator transition in VO${}_2$
• Valence bond crystal in a pyrochlore antiferromagnet with orbital degeneracy
• Orbitally driven spin-singlet dimerization in $S$=1 La${}_4$Ru${}_2$O${}_{10}$

Cited by in corpus (5)

• Orbital-spin order and the origin of structural distortion in MgTi${}_2$O${}_4$
• Ionic liquid gating induced two superconductor-insulator phase transitions in spinel oxide Li${}_{1\pm x}$Ti${}_2$O${}_{4-\delta }$
• On the complexity of spinels: Magnetic, electronic, and polar ground states
• Evolution of orbital excitations from insulating to superconducting MgTi${}_2$O${}_4$ films
• Exploring the Electronic Nature of Spinel Oxides: A Review of Their Electron Interactions and Prospects