  In scaling of transistor dimensions with low source-to-drain currents, 1D
semiconductors with certain electronic properties are highly desired. We
discover three new 1D materials, SbSeI, SbSI and SbSBr with high stability and
novel electronic properties based on first principles calculations. Both
dynamical and thermal stability of these 1D materials are examined. The
bulk-to-1D transition results in dramatic changes in band gap, effective mass
and static dielectric constant due to quantum confinement, making 1D SbSeI a
highly promising channel material for transistors with gate length shorter than
1 nm. Under small uniaxial strain, these materials are transformed from
indirect into direct band gap semiconductors, paving the way for optoelectronic
devices and mechanical sensors. Moreover, the thermoelectric performance of
these materials is significantly improved over their bulk counterparts.
Finally, we demonstrate the experimental feasibility of synthesizing such
atomically sharp V-VI-VII compounds. These highly desirable properties render
SbSeI, SbSI and SbSBr promising 1D materials for applications in future
microelectronics, optoelectronics, mechanical sensors, and thermoelectrics.
