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CsV3Sb5 DFT

DFT Calculations and Properties

CsV3Sb5_bands.png

  1. Multiple bands crossing the Fermi level (\(E_F\)) in \(CsV_3Sb_5\)
  2. Around the Γ point, there is an electron-like parabolic band, which originates from the in-plane Sb \(p_z\) orbital.
  3. The bands around the Brillouin zone (BZ) boundaries are mainly attributed to the V d orbitals.
  4. Two van Hove (VH) points close to \(E_F\) around the M point, which play an important role in the symmetry breaking observed in \(AV_3Sb_5\).
  5. The upper VH point is further connected with the Dirac cone around the K point, which reflects a typical feature of the kagome model.

ARPES

CsV3Sb5_ARPES.png ARPES and DFT data tracing reveal multiple Dirac points throughout the dispersion.

Phonon Calculation

CsV3Sb5_phonon_calc.png

Phonon spectrum

  • There are two negative energy soft modes around the M and L points respectively, leading to structural instabilities
  • Star of David(SoD) and Tri-Hexgonal(TrH) are likely candidates for CDW structures.

CsV3Sb5_SoD_TrH.png

(b):SoD (c): TrH

Tri-Hexagonal(TrH) is also known as Inverse Star of David.