Fermi surface and interlayer transport in high-stage $\mathrm{Mo}{\mathrm{Cl}}_5$ graphite intercalation compounds

Shubnikov–de Haas (SdH) and angular-dependent magnetoresistance oscillations (AMRO’s) in high-stage $\mathrm{Mo}{\mathrm{Cl}}_5$ graphite intercalation compounds are reported. Several SdH oscillations and AMRO’s are observed; however, the background of the angular-dependent magnetoresistance cannot be interpreted by the semiclassical model based on the Boltzmann coherent transport theory. A resistance peak in magnetic fields parallel to the conducting layers is clearly observed, demonstrating coherent transport. The results are discussed in terms of an incoherent motion crossing the magnetic intercalate layers and a coherent motion only in the graphite layers.

Figure 1

(a) Field dependence of the interlayer resistance of stage-5 $\mathrm{Mo}{\mathrm{Cl}}_5$ GIC at $1.0\mathrm{K}$. Shubnikov–de Haas oscillations are observed at $\theta =0°$. Angle $\theta$ is defined in the inset. (b) Fourier transform spectrum of the SdH oscillations.

Figure 2

FT amplitudes of the SdH oscillations divided by temperature vs temperature. The solid lines are the fitted results with the Lifshitz-Kosevich formula.

Figure 3

SdH frequencies as a function of the magnetic field angle $\theta$. The solid lines show $1∕\cos \theta$ dependences.

Figure 4

(a) Angular-dependent magnetoresistance for different magnetic fields at $T=1.7\mathrm{K}$. (b) The normalized curves $R(B,\theta )∕R(B,90°)$ for magnetic fields close to the conducting layers. The arrows denote the AMRO peaks.

Figure 5

Second-derivative curve of AMRO as a function of $\tan \theta$. The oscillatory behavior at $\mid \tan \theta \mid \lesssim 2.5$ is caused by the SdH oscillations. The arrows correspond to the AMRO peaks presented in Fig. 4b.

Figure 6

(a) Interlayer resistance close to $\theta =90°$ for stages-3, -4, and -5 $\mathrm{Mo}{\mathrm{Cl}}_5$ GIC’s. (b) Second-derivative curves of the resistance. Each curve is shifted for clarity.

Figure 7

Schematic picture of the coherent and incoherent transport for a stage-5 $\mathrm{Mo}{\mathrm{Cl}}_5$ GIC in (a) $k$ space and (b) real space. Solid and dashed curves denote the trajectories corresponding to the coherent and incoherent transport, respectively.