We consider a two-dimensional electron system with Coulomb interaction between particles at a finite temperature $T$. We show that the dynamic Kohn anomaly in the response function at $2k_F$ leads to a nonanalytic, linear-in-$T$ correction to the spin susceptibility, $\delta \chi \left(T\right)=aT$, the same as in systems with short-range interaction. We show that the singularity of the Coulomb interaction at $q=0$ does not invalidate the expansion of the prefactor $a$ in powers of $r_s$, but makes the expansion nonanalytic.

• Received 1 January 2005

DOI:https://doi.org/10.1103/PhysRevB.71.201302