Unveiling the orbital-selective electronic band reconstruction through the structural phase transition in TaTe${}_2$

Abstract

Tantalum ditelluride TaTe${}_2$ belongs to the family of layered transition metal dichalcogenides but exhibits a unique structural phase transition at around 170 K that accompanies the rearrangement of the Ta atomic network from a "ribbon chain" to a "butterfly-like" pattern. While multiple mechanisms including Fermi surface nesting and chemical bonding instabilities have been intensively discussed, the origin of this transition remains elusive. Here we investigate the electronic structure of single-crystalline TaTe${}_2$ with a particular focus on its modifications through the phase transition, by employing core-level and angle-resolved photoemission spectroscopy combined with first-principles calculations. Temperature-dependent core-level spectroscopy demonstrates a splitting of the Ta $4f$ core-level spectra through the phase transition indicative of the Ta-dominated electronic state reconstruction. Low-energy electronic state measurements further reveal an unusual kink-like band reconstruction occurring at the Brillouin zone boundary, which cannot be explained by Fermi surface nesting or band folding effects. On the basis of the orbital-projected band calculations, this band reconstruction is mainly attributed to the modifications of specific Ta $5d$ states, namely the $d_{XY}$ orbitals (the ones elongating along the ribbon chains) at the center Ta sites of the ribbon chains. The present results highlight the strong orbital-dependent electronic state reconstruction through the phase transition in this system and provide fundamental insights towards understanding complex electron-lattice-bond coupled phenomena.

The final version is available in Phys. Rev. Res. (Open Acess)

References in corpus (7)

• Fermi surface nesting and the origin of Charge Density Waves in metals
• Classification of Charge Density Waves Based on Their Nature
• Unfolding first-principles band structures
• A precise method for visualizing dispersive features in image plots
• Switching of band inversion and topological surface states by charge density wave
• A novel $\sqrt{19}\times \sqrt{19}$ superstructure in epitaxially grown 1T-TaTe${}_2$
• Observation of local atomic displacements intrinsic to the double zigzag chain structure of 1T-MTe2 (M = V, Nb, Ta)

Cited by in corpus (4)

• Femtosecond trimer quench cycled at megahertz rates in the unconventional charge-density wave material $1\text{T’}-{\text{TaTe}}_2$
• Unusual photoinduced crystal structure dynamics in TaTe${}_2$ with double zigzag chain superstructure
• Electronic Landscape of Group-5 Transition Metal Ditellurides $M$Te${}_2$ ($M$ = V, Nb, Ta): Multiple Crystal Phases with Local Bonds and Flat Bands
• The rich structural, electronic and bonding landscape of 1$T$-type TaTe${}_2$ single-layers