Nonlinear transport and low temperature phase transition in polar semimetal MoTe₂

Inversion symmetry breaking in van der Waals materials plays important roles in their emergent optical and transport properties. Examples include valley Hall effect in monolayer MoS₂ [1] and nonlinear anomalous Hall effect in few layer WTe₂ [2,3]. Among the noncentrosymmetric van der Waals crystals, T_d-MoTe₂ shows a reversible thermally driven phase transition at T_c ~ 250 K between centrosymmetric 1T’ phase (high temperature) and noncentrosymmetric T_d phase (low temperature) [4], offering a platform for investigating the symmetry-related physical properties.

In this work, we report nonlinear magnetotransport [5] in T_d-MoTe₂. Firstly, we observed the slight anomaly in linear resistance far below T_c ~ 250 K (T* ~ 50 K), which might imply another phase transition in T_d phase MoTe₂. Secondly, we found that the nonlinear magnetoresistance is suppressed above T* although T_d phase might persist. We assume that the low temperature phase transition at T* might be a key ingredient of the nonlinear transport properties in T_d-MoTe₂.

[1] K. F. Mak et al., Science 344, 1489 (2014).

[2] Q. Ma et al., Nature 565, 337–342 (2019).

[3] K. Kang et al., Nat. Mater. 18, 324–328 (2019).

[4] K. Zhang et al., Nat. Commun. 7, 13552 (2016).

[5] T. Ideue and Y. Iwasa, Annu. Rev. Condens. Matter Phys. 12, 201 (2021).