Small Wavevector–Dependent Spin Susceptibility in Weyl Semimetals

Abstract

A detailed derivation of the off‐diagonal spin–spin correlation functions of 3D Weyl semimetals in the static ω = 0 limit for small wavevectors at zero temperature is presented. The real part of the spin correlation function is evaluated analytically and follows ln(W/|μ|) behavior, with W and μ being the high‐energy cutoff and chemical potential, respectively. Its imaginary part grows linearly with μ. These quantities are also evaluated using brute force numerical integration, and the numerical data agree convincingly with the analytical result. This work provides the starting point to determine the Knight shift of Weyl semimetals from the hyperfine coupling through the wavevector‐dependent susceptibility.