Electronic properties and phonon-limited carrier mobility in Janus CrBZTe₂ (Z = N, P, As) monolayers: A first-principles study

Abstract

In this work, we systematically investigate the structural, electronic, and carrier transport properties of Janus CrBZTe₂ (Z = N, P, and As) monolayers by using density functional theory. The calculations indicate that these Janus materials are dynamically and energetically stable, suggesting that they could be synthesised via conventional experimental techniques. While a CrBNTe₂ monolayer exhibits metallic behaviour, CrBPTe₂ and CrBAsTe₂ monolayers are direct band-gap semiconductors with relatively small band gaps of 0.83 and 0.72 eV, respectively, as obtained from HSE06 hybrid functional calculations. The out-of-plane structural asymmetry gives rise to a difference in the vacuum levels between the two surfaces of the proposed Janus CrBZTe₂ materials. Carrier mobility is further analysed by considering multiple scattering mechanisms to ensure reliable transport predictions. The results show that the semiconducting monolayers exhibit relatively low carrier mobility, with transport primarily limited by acoustic deformation-potential scattering. These findings provide fundamental insights into the physical properties of Janus monolayers and highlight their potential for future electronic applications.