Observation of orbital order in the Van der Waals material 1T-TiSe2

Abstract

Besides magnetic and charge order, regular arrangements of orbital occupation constitute a fundamental order parameter of condensed matter physics. Even though orbital order is difficult to identify directly in experiments, its presence was firmly established in a number of strongly correlated, three-dimensional Mott insulators. Here, reporting resonant X-ray scattering experiments on the layered Van der Waals compound $1T$-TiSe${}_2$, we establish the emergence of orbital order in a weakly correlated, quasi-two-dimensional material. Our experimental scattering results are consistent with first-principles calculations that bring to the fore a generic mechanism of close interplay between charge redistribution, lattice displacements, and orbital order. It demonstrates the essential role that orbital degrees of freedom play in TiSe${}_2$, and their importance throughout the family of correlated Van der Waals materials.

References in corpus (8)

• 2D materials and van der Waals heterostructures
• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Controlling many-body states by the electric-field effect in a two-dimensional material
• Material design with the van der Waals stacking of bismuth-halide chains realizing a higher-order topological insulator
• Optical detection and manipulation of spontaneous gyrotropic electronic order in a transition-metal dichalcogenide semimetal
• Phonon collapse and van der Waals melting of the 3D charge density wave of VSe${}_2$
• Correlation between electronic and structural orders in 1T-TiSe2
• Reply to: 'Comment on: "The chiral phase transition in charge ordered 1T-TiSe${}_2$" '

Cited by in corpus (7)

• Coexistence of Multiple Stacking Charge Density Waves in Kagome Superconductor ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$
• Observation of giant circular dichroism induced by electronic chirality
• Lattice-Driven Chiral Charge Density Wave State in 1T-TaS${}_2$
• In-plane anisotropy of charge density wave fluctuations in 1$T$-TiSe${}_2$
• Doping-induced nematic and stripe orders within the charge density wave state of TiSe${}_2$
• Orbital Ordering in the Charge Density Wave Phases of BaNi${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$