  In this work, Dirac fermions have been obtained and engineered in
one-dimensional (1D) zigzag phosphorus nanotubes (ZPNTs). We have performed a
comprehensive first-principle computational study of the electronic properties
of ZPNTs with various diameters. The results indicate that as the lattice
parameter (Lc) along axial direction increases, ZPNTs undergo transitions from
metal to semimetal and semimetal to semiconductor, whereas Dirac fermions
appear at Lc ranging from 3.90{\AA} to 4.10{\AA}. In particular, a field effect
transistor (FET) based on a 12-ZPNT (with 12 unit cells in transverse
direction) exhibits semiconductor behaviors with efficient gate-effect
modulation at Lc= 4.60{\AA}. However, only weak gate modulation is demonstrated
when the nanotube becomes semimetal at Lc= 4.10{\AA}. This study indicates that
ZPNTs are profoundly appealing in applications in the strain sensors. Our
findings pave the way for development of high-performance strain-engineered
electronics based on Dirac Fermions in 1D materials.
