Extended Kohler's scaling, a low temperature anomaly and Isosbestic point in the charge density wave state of 1T-VSe${}_2$

Abstract

1T-VSe${}_2$ is a narrow band transition metal chalcogenide that shows charge density wave (CDW) state below $T_{CDW}$ = 110 K. Here, we have explored the relevance of Kohler's rule and the thermal transport properties of VSe${}_2$ across the CDW state. The magnetoresistance (MR) follows Kohler's rule above $T_{CDW}$, while an extended Kohler's rule is employed below $T_{CDW}$. Interestingly, we observed an anomaly in MR at T = 20 K, below which MR value decreases on lowering temperature. This anomaly is also reflected in the slope ($\hat{I}º$) of Kohler's plots and the relative change in the thermal excitation induced carrier density ($n_T$) also. The $T_{CDW}$ remains largely unaffected in both electrical resistivity ($\ddot{I}(T)$) and longitudinal Seebeck coefficient ($S_{xx}$) even under a strong magnetic field of 14 Tesla. However, the application of magnetic field enhances the peak intensity of $S_{xx}$ at T $\sim$ 60 K. Additionally, $S_{xx}(T)$ curves measured at different fields exhibit a crossover at T = 20 K, which suggest the existence of unique feature in the CDW state of VSe${}_2$ \textit{i.e.} a locally exact isosbestic point.

10 pages, 5 figures