  Most recently, F-diamane monolayer was experimentally realized by the
fluorination of bilayer graphene. In this work we elaborately explore the
electronic and thermal conductivity responses of diamane lattices with homo or
hetero functional groups, including: non-Janus C2H, C2F and C2Cl diamane and
Janus counterparts of C4HF, C4HCl and C4FCl. Noticeably, C2H, C2F, C2Cl, C4HF,
C4HCl and C4FCl diamanes are found to show electronic diverse band gaps of,
3.86, 5.68, 2.42, 4.17, 0.86, and 2.05 eV, on the basis of HSE06 method
estimations. The thermal conductivity of diamane nanosheets was acquired using
the full iterative solutions of the Boltzmann transport equation, with
substantially accelerated calculations by employing machine-learning
interatomic potentials in obtaining the anharmonic force constants. According
to our results, the room temperature lattice thermal conductivity of graphene
and C2H, C2F, C2Cl, C4HF, C4HCl and C4FCl diamane monolayers are estimated to
be 3636, 1145, 377, 146, 454, 244 and 196 W/mK, respectively. The underlying
mechanisms resulting in significant effects of functional groups on the thermal
conductivity of diamane nanosheets were thoroughly explored. Our results
highlight the substantial role of functional groups on the electronic and
thermal conduction responses of diamane nanosheets.
