The importance of various contributing mechanisms to the magnetic susceptibility χ and Knight shift K of ${\mathrm{Pb}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Sn}}_{\mathrm{x}}$Te is analyzed using a k⋅π perturbation theory. It is found that the spin contributions, ${\chi }_s$ and $K_s$, are the dominant terms. However, with increase in carrier concentration, the strengths of ${\chi }_{\mathrm{so}}$ and $K_{\mathrm{so}}$ increase, and become of the same order as ${\chi }_s$ and $K_s$, respectively. While ${\chi }_o$ is of the same order as ${\chi }_s$, but with a negative sign, $K_o$ is three orders less than $K_s$. It is also found that electron-electron exchange enhancement increases with increase in the carrier density. However, both χ and K remain virtually unaffected by electron-electron interaction because the maximum carrier density considered is about four orders less than the metallic density where the exchange enhancement is significant. With alloying, i.e., with increase in tin concentration, both χ and K decrease for a fixed carrier density, with reference to the corresponding values in PbTe. This and other features considered are in overall agreement with the experimental results.

• Received 14 June 1989

DOI:https://doi.org/10.1103/PhysRevB.40.11168