Dirac-like band structure and strain-tunable electronic structure of Zr2CCl2 monolayer

Highlights: • The Zr₂CCl₂-III monolayer has a Dirac-like cone near the Fermi level. • By considering the spin-orbit coupling, the splitting value of Zr₂CCl₂-III becomes larger. • Electronic structure of Zr₂CCl₂-III can be tunable by strain. Two dimensional MXenes is a general term for transition metal carbides and their derivatives. Different MXenes materials have attracted much attention due to their unique electronic properties, which have the potential applications in spintronic devices. With the synthesis of two dimensional Zr-containing materials, the related two dimensional Zr MXenes materials have gradually been paid more attention, so theoretical research based on first principles has also been enriched. In this paper, the electronic structure of the two dimensional MX Zr₂C material after adsorption of Cl functional groups at different symmetrical positions on both sides is studied systematically by using the density functional theory. The bare Zr₂C is a metal with magnetism, while the Zr₂CCl₂ structure becomes a non-magnetic metal. Three adsorption structures of Zr₂CCl₂ have been studied. The Zr₂CCl₂-I monolayer is the most stable structure, but the Zr₂CCl₂-II monolayer is the only unstable structure among the three structure. Additionally, a Dirac-like structure with a tiny gap appears in Zr₂CCl₂-III monolayer, where the position of gap can be further tailored by biaxial strain. As the compressive strain increases, the Dirac-like will move up. Moreover, at a compressive strain of −0.9%, the Dirac-like structure of Zr₂CCl₂-III will move to the Fermi level with an indirect-band-gap of 7.3 meV. At the same time, considering the influence of SOC, its band gap value will become 29.3 meV. The Dirac-like structure with a band gap also makes up for the shortcoming of graphene's zero band gap. And Zr₂C with different functional groups has different electronic properties, since Zr₂C MXenes have potential applications in electronic devices.