Molecular Beam Epitaxy Growth and Doping Modulation of Topological Semimetal NiTe$_2$

TL;DR

This paper reports the growth of high-quality NiTe2 thin films via MBE, demonstrating how magnetic doping induces ferromagnetism and Weyl semimetal states, with implications for quantum device applications.

Contribution

It introduces a method to modulate the topological and magnetic properties of NiTe2 thin films through controlled doping during MBE growth.

Findings

Magnetic doping induces ferromagnetic order in NiTe2 films.

Anomalous Hall effect observed correlating with magnetic doping.

Theoretical calculations confirm Weyl semimetal state generation.

Abstract

In this study, high-quality thin films of the topological semimetal phase NiTe$_2$ were prepared using molecular beam epitaxy (MBE) technique, confirmed through X-ray diffraction with pronounced Laue oscillations. Electrical transport experiments reveal that thick films have properties similar to bulk materials. By employing co-deposition, we introduced either magnetic or non-magnetic elements during the growth of thinner films, significantly altering their electrical properties. Notably, magnetic element Cr induces long-range ferromagnetic ordering, leading to the observation of significant anomalous Hall effect in NiTe2 thin films. The Hall conductivity remains nearly constant well below the Curie temperature, indicating the correlation with the intrinsic topological nature of the band structure. Theoretical first principles band calculations support the generation of the Weyl semimetal state in the material through magnetic doping. These findings pave the way for exploring more magnetic Weyl semimetal materials and related low-dimensional quantum devices based on topological semimetal materials.