Transport characteristics of type II Weyl semimetal MoTe₂ thin films grown by chemical vapor deposition

Abstract

Theoretical calculations and experimental observations show MoTe 2 is a type II Weyl semimetal, along with many members of transition metal dichalcogenides family. We have grown highly crystalline large-area MoTe 2 thin films on Si/SiO 2 substrates by chemical vapor deposition. Very uniform, continuous, and smooth films were obtained as confirmed by scanning electron microscopy and atomic force microscopy analyses. Measurements of the temperature dependence of longitudinal resistivity and current-voltage characteristics at different temperature are discussed. Unsaturated, positive quadratic magnetoresistance of the as-grown thin films has been observed from 10 K to 200 K. Hall resistivity measurements confirm the majority charge carriers are hole.

Molecular beam epitaxy growth of nonmagnetic Weyl semimetal LaAlGe thin film

“…There are no previous reports on thin films LaAlGe to compare the longitudinal resistivity; nevertheless, resistivity reported at room temperature for its single crystal is ~ 68  cm [17], which is close to our observation. The estimated residual resistivity ratio (RRR) 𝜌 𝑥𝑥 (300 K)/𝜌 𝑥𝑥 (5 K) is 1.17 which is comparatively low even for semimetal [20,21], however it is very close to that reported for flux-grown single-crystals LaAlGe (~2) [17]. It is also comparable with its isostructural family members, for example, the RRR values of bulk single crystals CeAlGe [17] and PrAlGe [4], grown by flux-method, has been reported ~2.…”