We present a renormalization-group study of quantum tricriticality in metals. We evaluate the correlation length in the quantum critical region of the phase diagram, extending into finite temperatures above the quantum critical or tricritical point. We calculate the finite temperature phase boundaries and analyze the crossover behavior when the system is tuned between quantum criticality and quantum tricriticality. Interactions between order-parameter fluctuations are usually overshadowed by generic (noncritical) temperature dependences in the quantum tricritical regime.

• Received 5 February 2010

DOI:https://doi.org/10.1103/PhysRevB.82.045103