The Effect of Rashba Spin-Orbital Coupling on Electronic Spin Susceptibility

The effect of the Rashba spin-orbital coupling on the spin susceptibility of an electronic system strongly correlated with a two-dimensional square lattice is studied. According to the linear response theory, spin susceptibility can be expressed with a retarded Green function. The equations of the spin susceptibility can be numerically solved with a random phase approximation and a Hartree-Fock approximation. The numerical results show that in the absence of spin-orbital coupling the static spin susceptibility Reχ( q ; ω=0) increases with the increase of the Coulomb interaction U and decreases with increasing temperature. The Coulomb interaction U and temperature T have similar effects on the dynamic susceptibility Reχ( q ; ω=0). When the spin orbital coupling is added into the system, the real part of the spin susceptibility χ( q ) shows a flat base around the q =0. The size of the flat base increases significantly with increasing V_SO while the imaginary part ofχ( q ) shows a drastic fluctuation at the boundary of the flat base. Thus, this effect becomes a clear signature of the spin-orbital coupling of a system.