Strain-engineered conductivity transition and its mechanism in Bi (110) Film

• Published in: Surfaces and interfaces 2025-01, Vol.56, Article 105595
• Main Authors: Liu, Y.L., Ma, X.H., Jia, W.P., Ren, S.H., Zhang, H., Qi, Y.
• Format: Article
• Language: English
• Subjects: Electronic properties; First-principles methods; Strain effect; αω-Bi; ω-Bi
• ISSN: 2468-0230
• DOI: 10.1016/j.surfin.2024.105595

Bi thin films are narrow band gap materials with high carrier mobility, stability and good ductility. Strain engineering is effective for regulation of electronic properties of Bi films. But for Bi (110) film, the strain regulation mechanism of ω-Bi(110) to αω-Bi(110) transition and its electronic properties variation under different strain modes and thickness remain unclear. In this paper, we systemically studied the strain regulation mechanism of Bi (110) film based on density functional theories. It is found that, αω-Bi structure possesses better stability, toughness and obvious atomic buckling than ω-Bi (110), and ω-Bi can transform into αω-Bi by the deformation induced buckling. For αω-Bi, compress strain tends to induce the transition of semimetal to metal, the tensile strain may induce transition of conduction band minimum (CBM) and valence band maximum (VBM) due to the competition between band edge states, and the in-plane strain can cause the band splitting. Meanwhile, the uniaxial strain can effectively reduce the effective mass of electron and hole, leading to the improvement of the carrier mobility of αω-Bi. The present research predicts the great application potential of αω-Bi (110) film in area of semiconductor electronic devices, and provides the detailed regulation rules of conductivity of the αω-Bi by strain. [Display omitted]