A 2D heavy fermion CePb3 kagome material on silicon: emergence of unique spin polarized states for spintronics

We report on the successful synthesis of a 2D atomically thin heavy-fermion CePb3 kagome compound on a Si(111) surface. Growth and morphology were controlled and characterized through scanning tunneling microscopy observations revealing the high crystalline quality of the sample. Angle-resolved photoelectron spectroscopy measurements revealed the giant highly-anisotropic Rashba-like spin splitting of the surface states and semi-metallic character of the spectrum. According to the DFT calculations, the occupied hole and unoccupied electron states with huge spin–orbit splitting and out-of-plane spin polarization reside at the M points near the Fermi level EF, which is ≈100 meV above the experimental one. The out-of-plane FM magnetization was found to be preferred with Ce spin and orbital magnetic momenta values of 0.895μB and −0.840μB, respectively. The spin-split states near EF are primarily formed by Pb pxy orbitals with the admixing of Ce d and f electrons due to the Ce f–d hybridization acquired asymmetry with respect to the sign of k∥. The observed electronic structure of the CePb3/Si(111)√3 × √3 system is rather unique and in the hole-doped state, like in our experiment, can be enabled in the tunable spin current regime, which makes it a prospective 2D material for spintronic applications.