A family of robust Dirac cone materials: two-dimensional hexagonal M3X2 (M = Zn/Cd/Hg, X = Si/Ge). Issue 15 (3rd April 2023)

• Record Type: Journal Article
• Authors: Li, Qiuyang; Yan, Cuixia; Qi, Chenchen; Qiu, Shi; Yang, Ting; Cai, Jinming
• Is Part Of: Physical chemistry chemical physics. Volume 25:Issue 15(2023)
• Page Start: 10811
• Page End: 10819
• Publication Date: 2023-04-03
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp05494a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The first-principles calculations shows that the 2D Dirac cone material M3 X2 (M = Zn/Cd/Hg, X = Si/Ge) with a highly fermi velocity and possess a robust Dirac cone even under biaxial strain or being sheared into one-dimensional zigzag nanoribbons. Abstract : The fascinating Dirac cone, which has produced some excellent properties in graphene, such as ballistic charge transport, ultra-high carrier mobility and the quantum Hall effect, has motivated researchers to design and study more two dimensional (2D) Dirac materials. In this work, we have designed a family of 2D Dirac cone materials M3 X2 (M = Zn/Cd/Hg, X = Si/Ge) and studied their superior properties by first principles calculation. The calculated cohesive energy, phonon dispersion and ab initio molecular dynamics confirmed the energetic, dynamic and thermodynamic stability of Zn3 Ge2, Cd3 Ge2, Hg3 Si2, and Cd3 Si2 monolayers. It was found that the intrinsic Dirac cones exist in the electronic structure of the Zn3 Ge2, Cd3 Ge2, Hg3 Si2 and Cd3 Si2 monolayers. Their Fermi velocities are from 3.26 × 10 5 m s −1 to 4.32 × 10 5 m s −1 (8.2 × 10 5 m s −1 for graphene). It is noteworthy that the Dirac cone in the M3 X2 structure is robust. It is independent of external strain (from −7% to +19%) and can also be preserved as one-dimensional zigzag nanoribbons and multilayers (from two to three-layers). Our work shows that the novel M3 X2 Dirac cone materials are an important candidate for high-speed nanoelectronic devices.