  Transition metal dichalcogenides (TMDCs) usually exhibit layered polytypic
structures due to the weak interlayer coupling. 2H-NbSe2 is one of the most
widely studied in the pristine TMDC family due to its high superconducting
transition temperature (Tc = 7.3K) and the occurrence of a charge-density wave
(CDW) order below 33 K. The coexistence of CDW with superconductivity poses an
intriguing open question about the relationship between Fermi surface nesting
and Cooper pairing. Past studies of this issue have mostly been focused on
doping 2H-NbSe2 by 3d transition metals without significantly changing its
crystal structure. Here we replaced the Se by Te in 2H-NbSe2 in order to design
a new 1T polytype layered TMDC NbSeTe, which adopts a trigonal structure with
space group P-3m1. We successfully grew large size and high-quality single
crystals of 1T-NbSeTe via the vapor transport method using I2 as the transport
agent. Temperature-dependent resistivity and specific heat data revealed a bulk
Tc at 1.3 K, which is the first observation of superconductivity in pure
1T-NbSeTe phase. This compound enlarged the family of superconducting TMDCs and
provides an opportunity to study the interplay between CDW and
superconductivity in the trigonal structure.
