Magnetoresistance and Shubnikov–de Haas oscillations in layered ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$ thin flakes

We present the magnetoresistance (MR) and Hall resistivity of layered ternary ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$ thin flakes with magnetic field up to 33 T. The flakes show strong angle-dependent MR properties and unsaturated quasilinear dependence accompanied with Shubnikov–de Haas (SdH) oscillations. Hall resistivity study demonstrates that the hole carriers dominate the transport properties in the whole temperature range. The angle-dependent SdH oscillations reveal a two-dimensional Fermi surface of ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$. Furthermore, by analysis of SdH oscillations, we observed a nontrivial $\pi$-Berry phase in the SdH oscillations which suggests the nontrivial topological nature of ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$.

Figure 1

(a) Longitudinal resistivity of ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$ single crystal in zero magnetic field for sample S1 (26 nm) and sample S2 (12 nm) from 2 to 300 K. The upper inset shows the crystal structure of ${\mathrm{Nb}}_3\mathrm{Si}{\mathrm{Te}}_6$. The lower inset shows the scanning electron microscope image of a Hall bar device used in the measurement process. (b), (c) The MR with magnetic field applied perpendicular to the thin flake at various temperatures for sample S1 ($t=26$ nm) and S2 ($t=12$ nm), respectively. (d) Angle-dependent MR at 2 K for sample S1 ($t=26$ nm).

Figure 2

(a), (c) Respectively, the Hall resistance $R_{xy}$ of sample S1 ($t=26$ nm) and S2 ($t=12$ nm) as a function of magnetic field at various temperatures. (b), (d) Respectively, the temperature dependence of the mobility and the carrier density. The insets show the temperature dependence of the Hall coefficient $R_H$.

Figure 3

(a) The longitudinal resistance $R_{xx}$ of sample S2 ($t=12$ nm) as a function of magnetic field under different field orientation angles $\theta$. (b) The oscillatory component $\mathrm{\Delta }{R}_{xx}$, extracted from $R_{xx}$ by subtracting a smooth background, as a function of 1/$B\cos \left(\theta \right)$ at various angles.

Figure 4

(a) Longitudinal magnetoresistance of sample S2 ($t=12$ nm) at different temperatures with a maximum field of 33 T. The curves are shifted for clarity. (b) The oscillatory component $\mathrm{\Delta }{R}_{xx}$ as a function of 1/$B$ at various temperatures. (c) Temperature dependence of the scaled oscillation amplitude at $B=31$ T. The solid curves are the fits to the Lifshitz-Kosevich formula from 1.8 to 7 K. The inset shows the Dingle plot of the SdH oscillations at $T=3$ K. (d) Landau-level index $n$ extracted from SdH oscillations plotted as function of the 1/$B$.