Evidence of the ferroelectric polarization in charge transport through WTe$_2$ Weyl semimetal surface

Abstract

We investigate electron transport along the surface of WTe2 three-dimensional single crystals, which are characterized by coexistence of Weyl semimetal conductivity and ferroelectricity at room temperature. We find that non-linear behavior of dV /dI(I) WTe2 differential resistance is accompanied by slow relaxation process, which appears as the dV /dI(I) dependence on the sign of the current change. This observation is confirmed by direct investigation of time-dependent relaxation curves. While strongly non-linear differential resistance should be expected for the zero-gap WTe2, the slow relaxation in transport is very unusual for well-conducting semimetals at room temperature. We establish, that non-monotonous dependence of the amplitude of the effect on driving current ∆dV /dI(I) well corresponds to the known Sawyer-Tower's ferroelectric hysteresis loop. This conclusion is also confirmed by gate voltage dependencies, so our results can be understood as a direct demonstration of WTe2 ferroelectric polarization in charge transport experiment.

Switching ferroelectricity in SnSe across diffusionless martensitic phase transition

“…2 (a). In addition, we observe significant hysteresis with bias sweep direction, which somewhat analogous to the previously reported 32 for the ferroelectric chalcogenide WTe 2 : for opposite voltage sweep directions, there is noticeable discrepancy between the curves within the ±1 V range. It is important, that dI/dV (V ) curves coincide perfectly in Fig.…”

“…In general, hysteretic dI/dV (V ) behavior in Figs. 2, 4 and 5 (a) is qualitatively analogous to ferroelectricityinduced one 32 for another ferroelectric chalcogenide WTe 2 .…”

“…All the data are qualitatively similar to ones from the sample in Fig.2. In general, hysteretic dI/dV (V ) behavior with slow relaxation is analogous to ferroelectricity-induced one32 for another ferroelectric chalcogenide WTe2.…”