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AV6Sb6 family

\(AV_6Sb_6\) Family

The family of \(AV_6Sb_6\)(A=K, Rb, Cs) is a new class of bilayer kagome lattice compounds similar to AV3Sb5 family with Dirac nodal lines and other interesting properties. It shares AV3Sb5 general properties, like Dirac nodal lines, Superconductivity under pressure.

Structure

Structure Comparison(AV3Sb5 and AV6Sb6 comparison#Structure)

AV3Sb5_AV6Sb6_str_compare.png

Pressure-induced Superconductivity

These do not exhibit Superconductivity at ambient pressure, although it is realized by applying quasi-hydrostatic pressure.

Phase_Diagram_CsV6Sb6.png Phase Diagram (RRR : Residual Resistivity Ratio)

  • The T-dependence of the normalized resistance(\(R/R_{300K}\)) show metallic behavior in the entire pressure range with RRR gradually decreases below 15GPa.
  • Superconducting transition emerges at 21.2 GPa manifested by Resistance drop.
  • \(T_c^{90\%}\) is 1.04K
  • Evolution of \(T_c\) : Non-monotonic
  • Superconductivity persists up to around 80 GPa.
  • Superconducting Dome is observed for all family members.
  • Superconductivity in all the materials appears in the vicinity of RRR, implying that emergence of superconductivity is associated with electronic structure modifications.
  • Structural phase transition occurs above 20 GPa, where structure changes from rhombohedral to monoclinic.
  • It is likely that Monoclinic phase hosts the Superconductivity.

Related Links: 1. AV6Sb6 DFT 2. AV3Sb5 and AV6Sb6 comparison 3. Original Paper : A new class of bilayer kagome lattice compounds with Dirac nodal lines and pressure-induced superconductivity (Link)