Direct observation of hidden spin polarization in 2H-MoT e2

Centrosymmetric (CS) nonmagnetic materials with hidden spin polarization induced by non-CS site symmetries and spin-orbit coupling are promising candidates for spintronic applications, in light of the zero net spin polarization and modulatable spin effects hidden in the local structures. There is, however, an open issue regarding the possible spin splitting induced by broken inversion symmetry at the sample surface. Here, we performed combinatorial experimental and theoretical studies on the potentially hidden spin polarization in 2H-MoTe2 and its mechanism. A large spin splitting of 236 meV and opposite spin polarizations up to 80% along out-of-plane direction (z axis) in K and K′ valleys were observed from both spin- and angle-resolved photoemission spectroscopy (spin-ARPES) and density functional theory (DFT). We further found from the DFT calculations that a medium dipole field mimicked the surface symmetry breaking in ARPES measurements induces negligible variation of spin polarization. Our study demonstrates the existence of the intrinsic hidden spin effects in 2H-MoTe2 and opens a way of utilizing these effects in spintronic devices.