  The already intriguing electronic and optical properties of the MXene Sc2C
family can be further tuned through a wide range of possible
functionalizations. Here, by means of Density Functional Theory, we show that
the 36 possible elements of the Janus MXT (M:Sc2C, X:O, F, OH, T:C, N, S)
family, built by considering the four possible structural models (i) FCC, (ii)
HCP , (iii) FCC + HCP, and (iv) HCP + FCC, are all potentially stable. The
analysis of their mechanical properties shows the excellent mechanical
flexibility of functionalized MXenes (f-MXenes) under large strain, making them
more suitable for applications where stress could be an issue. Interestingly,
while Sc2C presents a metallic character, Sc2COS, Sc2CFN and Sc2COHN are found
to be semiconductors with bandgaps of 2.5 eV (indirect), 1.67 eV (indirect) and
1.1 eV (direct), respectively, which presents promising applications for nano-
and optoelectronics. Moreover, Sc2CFC presents a ferromagnetic ground state
with the 2x2x1 supercell magnetic moment of 3.99 muB, while the ground state of
Sc2COHC might be antiferromagnetic with a magnetic moment of 3.98 muB,
depending on the environment. Remarkably, the band structures of Sc2CFC and
Sc2COHC present a half-metallic character with an HSE06 fundamental band gap of
0.60 eV and 0.48 eV, respectively. Our results confirm the extraordinary
potential of the Janus MXT (M:Sc2C, X:O, F, OH, T:C, N, S) family for novel
applications in 2D nano-,opto- and spintronics.
