  It is shown that the band structure of single-wall semiconducting carbon
nanotubes (CNT) is analogous to relativistic description of electrons in
vacuum, with the maximum velocity $u$= $10^8$cm/s replacing the light velocity.
One-dimensional semirelativistic kinematics and dynamics of electrons in CNT is
formulated. Two-band k.p Hamiltonian is employed to demonstrate that electrons
in CNT experience a Zitterbewegung (trembling motion) in absence of external
fields. This Zitterbewegung should be observable much more easily in CNT than
its analogue for free relativistic electrons in vacuum.
