DFT Modeling of the Effect of Biaxial Strain on the Electronic Structure of Zigzag SWCNT for Applications as Nanoelectronic Switches

The strain-sensitive electronic properties of zigzag single-walled carbon nanotubes (zigzag SWCNT) exhibit enormous potential for applications in the field of nanoelectronic switches. To investigate the regulatory mechanism of biaxial strain on the electronic structure of zigzag SWCNT, this study employed density functional theory (DFT) combined with the GGA-PBE functional to systematically explore the evolutionary law of the electronic structure of 16 zigzag SWCNT with different chiral indices after direct curvature adjustment under x- and y-axis biaxial strain. The results show that biaxial strain exerts a significant modulation effect on the bandgap of zigzag SWCNT. Specifically, under 10% compressive strain, the bandgaps of the (12, 0) and (15, 0) SWCNT increase from 0.0902 and 0.0645 eV to 0.9997 and 0.9789 eV, respectively, realizing a reversible semiconductor–metal–semiconductor transition (SMST). This characteristic is highly consistent with the dynamic regulation requirements for the on–off state switching of nanoelectronic switches. A reasonable interpretation for this phenomenon is provided in this study based on the analysis of the structural evolution and projected density of states (PDOS) of the carbon nanotubes. Our work furnishes a key theoretical basis for understanding and realizing the precise regulation of the electronic structures of zigzag SWCNT via biaxial strain engineering, and it is of great significance for advancing their practical applications in the field of nanoelectronic switches.