Electronic properties of peanut-shaped single-walled carbon nanotubes under axial strain

In this work, we explore the properties of peanut-shaped single-walled carbon nanotubes (PSNTs), which are formed by introducing successive axial Stone-Wales (SW) defects into zigzag carbon nanotubes (CNTs). Employing first-principles calculations, we investigate the energetics of these defects and their effect on the structural, elastic, and electronic properties of the zigzag (10,0) CNT. Additionally, we examine the role of tensile and compressive axial strain in modifying the properties of these PSNTs. The results show significant reductions in band gaps, with distinct behaviors observed under different strain conditions. Notably, PSNTs exhibit strain-dependent electronic properties, including metal–semiconductor transformations and distinctive persistent metallic or semiconducting behavior under specific strain conditions. Furthermore, we find that the trend in variation in the band gap with strain is significantly influenced by changes in bond lengths, which vary depending on the type and magnitude of the applied strain. These findings provide insights into the tunability of CNT electronic properties through defect engineering and strain application, offering potential pathways for designing advanced nanoelectronic devices.