Theoretical Investigation of Anomalous Hall and Nernst Responses in Potassium Tri Vanadium Pentantimonide

Abstract

We present a theoretical study of the anomalous Nernst and Hall conductance in the Kagome metal potassium tri vanadium pentantimonide, based on a system Hamiltonian incorporating nearest neighbour and complex next nearest neighbour hopping, Rashba spin orbit coupling, an exchange field induced by magnetic proximity, and a charge density wave potential. Our analysis reveals that the Nernst conductivity exhibits a non monotonic temperature dependence. It increases with temperature, reaches a pronounced peak, and subsequently declines at higher temperatures due to thermal broadening, which diminishes the influence of Berry curvature. Notably, small shifts in the chemical potential can lead to dramatic changes in the Nernst signal enhancing its magnitude or even reversing its sign highlighting the system sensitivity to carrier density. We further explore the anomalous Hall behaviour within this framework. The band structure hosts multiple bands with nonzero Berry curvature, and preliminary Chern number calculations suggest weak topological features, namely, while not fully quantized, the system exhibits significant Berry curvature accumulation. Upon introducing momentum space winding, implemented via a momentum dependent phase in the complex hopping terms to mimic orbital magnetic flux, we observe that two bands acquire opposite Chern numbers. The remaining bands remain topologically trivial.