Research Projects

Kagome lattices have been a topic of interest in materials research and quantum physics for around seven decades. They possess exotic properties such as van Hove singularities, flat bands hosting electronic correlations, and Dirac cones indicating a nontrivial topology. The recent discovery of prototype kagome structure in compounds KV3Sb5, RbV3Sb5, and CsV3Sb5 has kagome nets of vanadium atoms. Density functional theory calculations predict magnetic behavior and multiple Dirac points. Magnetization measurements do not show any magnetic ordering, short range or long range, below 80K. The Kadowaki-Woods ratio in KV3Sb5 indicates correlated electron transport. AV3Sb5 (A=K,Rb,Cs) also show superconductivity at low temperature and charge ordering at relatively higher temperature. The direct band gap has a nontrivial ℤ2 topological index. The Fermi surface has van Hove singularities indicative of nesting instabilities. The latest family RV6Sn6 (R=Gd,Ho, Y) is reported to be kagome metals. The interplay of superconductivity and charge ordering concomitant with the topological nature of these kagome compounds merits exhaustive investigation using quasiparticle interference patterns as a window to the correlated electron behavior. A collaboration at IISER Pune has a scanning tunnelling microscope operating in ultrahigh vacuum and at 77 K and 4.2 K. Dr. Luminita Harnagea, a successful crystal grower with over a decade of experience in quantum materials, can contribute to this project by growing high-quality single crystals of KV3Sb5 and RbV3Sb5.