Topological Field-Effect Transistor Based on Quasi-Two-Dimensional Tellurium Flakes

For semiconductors, adding a degree of freedom beyond charge, e.g., spin and valley, will lead to alter-native physics and device applications. Here, we demonstrate that another electronic degree of freedom, the chirality of Weyl node, can be used in the Weyl semiconductor tellurium, a unique system harnessing intriguing Weyl physics and high tunability of the semiconductor. By constructing a field-effect device based on quasi-two-dimensional tellurium flakes, the Fermi level can be effectively tuned from the top of valence bands, where the Weyl nodes locate at, into the bandgap via electrostatic gating. In addition to a significant reduction of channel conductivity, a transition from chiral-anomaly-induced negative mag-netoresistance to conventional positive magnetoresistance occurs at the same time, indicating complete suppression of the chirality-related topological transport. The simultaneous switch of both conducting and topological states is unprecedented in previous Weyl semimetals. Our findings pave the way for developing new-principle semiconductor devices with fascinating functionalities.

Automated summary

This study demonstrates the use of chirality, a new electronic degree of freedom, in the tellurium semiconductor. By developing a field-effect device, the researchers were able to effectively control the Fermi level and observe the simultaneous switching of both conductivity and topological states.