Magnetism in AV_{3}Sb_{5} (A=Cs, Rb, and K): Origin and Consequences for the Strongly Correlated Phases

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• V-based kagome systems (AV_{3}Sb_{5}) display exotic phases like charge order and superconductivity.
• The interplay between magnetism, electronic structure, and collective phenomena remains unclear.

Purpose of the Study:

• Investigate the influence of electron correlations, spin-polarization, and spin-orbit coupling on electronic and phononic properties.
• Clarify the mechanism driving charge order in these materials.

Main Methods:

• First-principles calculations.
• Analysis of intersite magnetic exchanges.
• Study of electronic response functions and electron-phonon coupling.

Main Results:

• Electronic structures, fermiologies, and phonon dispersions are strongly affected by electron correlations, spin-polarization, and spin-orbit coupling.
• The system behaves as a frustrated spin cluster.
• Charge order is intimately related to electron-phonon coupling.

Conclusions:

• Electron-phonon coupling, not Fermi-surface nesting, is the primary mechanism for charge order in AV_{3}Sb_{5}.
• Understanding these interactions is key to exploring exotic quantum phenomena in kagome materials.