Probing the Hall anomaly and electronic structure in kagome metal RbV₃Sb₅ under hydrostatic pressure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Kagome metals AV3Sb5 (A=K, Rb, Cs) exhibit complex electronic structures relevant to topological states and electronic correlations.
• While CsV3Sb5 and KV3Sb5 are well-characterized, the electronic structure of RbV3Sb5 remains less understood.
• Understanding RbV3Sb5 is crucial for a comprehensive view of the AV3Sb5 family's properties.

Purpose of the Study:

• To investigate the electronic structure of RbV3Sb5 under varying pressures, particularly around the charge-density-wave (CDW) transition.
• To analyze the behavior of charge carrier mobilities and their relationship with the CDW phase and superconductivity.
• To explore potential correlations between carrier properties and the superconducting pairing mechanism in the AV3Sb5 family.

Main Methods:

• Shubnikov-de Haas (SdH) oscillations were measured at 9 kbar (CDW phase) and 22 kbar (CDW suppressed).
• Fast Fourier Transform (FFT) analysis of SdH data was used to probe Fermi surface reconstruction.
• Mobility Spectrum Analysis (MSA) was employed to study charge carrier mobilities across different pressure-induced phases.

Main Results:

• FFT spectra at 22 kbar suggest the absence of Fermi surface reconstruction upon CDW suppression.
• Enhanced quasi-particle effective masses near the CDW boundary indicate increased quantum fluctuations.
• MSA revealed the coexistence of high-mobility carriers (approx. 10,000 cm²/Vs) with a non-monotonic Hall effect at 9 kbar, which diminishes at higher pressures.
• The non-monotonic Hall effect and high-mobility carriers are suppressed as pressure increases to 22 and 30 kbar.

Conclusions:

• The electronic structure of RbV3Sb5 is significantly influenced by pressure and the CDW state.
• Enhanced quantum fluctuations occur near the CDW boundary.
• A positive correlation between superconducting behavior, carrier mobility, and carrier number was observed across the AV3Sb5 family.
• High-mobility carriers are suggested to play a key role in the superconducting pairing mechanism of these Kagome metals.