Competing charge-density wave instabilities in the kagome metal ScV₆Sn₆

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• The unique geometry of kagome lattices supports diverse quantum states like magnetism, superconductivity, and charge-density waves (CDWs).
• Scandium Vanadium Hexastannide (ScV6Sn6) is a kagome metal exhibiting complex electronic properties.

Purpose of the Study:

• To investigate the charge-density wave (CDW) formation and dynamics in the kagome metal ScV6Sn6.
• To understand the interplay between competing CDW instabilities and electron-phonon coupling (EPC).

Main Methods:

• Inelastic X-ray scattering (IXS) was employed to probe dynamic CDW correlations.
• First-principles calculations were used to determine energetic favorability and electron-phonon coupling characteristics.

Main Results:

• A dynamic, short-range [Formula: see text] CDW phase was observed above the transition temperature (T_CDW ≈ 91 K).
• This dynamic CDW competes with the lower-temperature, ordered [Formula: see text] CDW, leading to unusual CDW formation.
• First-principles calculations revealed that while [Formula: see text] CDW is energetically favored, wavevector-dependent EPC promotes the [Formula: see text] CDW and enhances electron scattering above T_CDW.

Conclusions:

• The study highlights the significant role of electron-phonon coupling in driving correlated many-body physics in ScV6Sn6.
• The findings suggest that ScV6Sn6 is a promising platform for exploring emergent quantum phases in the strong EPC regime.