  The possibility to achieve charge-to-spin conversion via Rashba spin-orbit
effects provide stimulating opportunities toward the development of nanoscale
spintronics. Here we use first-principles calculations to study the electronic
and spintronic properties of Tl$_2$O/PtS$_2$ heterostructure, for which we have
confirmed the dynamical stability by its positive phonon frequencies. An
unexpectedly high binding energy of -0.38 eV per unit cell depicts strong
interlayer interactions between Tl$_2$O and PtS$_2$. Interestingly, we discover
Rashba spin-splitting's (with large $\alpha_R$ value) in the valence band of
Tl$_2$O stemming from interfacial spin-orbit effects caused by PtS$_2$. The
role of van der Waals binding on the orbital rearrangements has been studied
using electron localization function and atomic orbital projections, which
explains in detail the electronic dispersion near the Fermi level. Moreover, we
explain the distinct band structure alignment in momentum space but separation
in real space of Tl$_2$O/PtS$_2$ heterostructure. Since 2D Tl$_2$O still awaits
experimental confirmation, we calculate, for the first time, the Raman spectra
of pristine Tl$_2$O and the Tl$_2$O/PtS$_2$ heterostructure and discuss peak
positions corresponding to vibrational modes of the atoms. These findings offer
a promising avenue to explore spin physics for potential spintronics
applications via 2D heterostructures.
