CRITICAL-BEHAVIOR OF THE UNIFORM SUSCEPTIBILITY OF A FERMI-LIQUID NEAR AN ANTIFERROMAGNETIC TRANSITION WITH DYNAMIC EXPONENT Z=2

We compute the leading behavior of the uniform magnetic susceptibility χ of a Fermi liquid near an antiferromagnetic transition with dynamic exponent z=2. Our calculation clarifies the role of triangular "anomaly" graphs in the theory and justifies the effective action used in previous work. We find that at the z=2 critical point of a two-dimensional material, limq→0χ(q,0)=χ0-D'T with χ0 and D' nonuniversal constants. For reasonable band structures, we find that in a weak-coupling approximation D' is small and positive. Our result suggests that the behavior observed in the quantum critical regime of underdoped high-Tc superconductors are difficult to explain in a purely z=2 theory. © 1995 The American Physical Society.