  We study the fixed-point structure of four-fermion interactions in two-flavor
QCD with Nc colors close to the finite-temperature phase boundary. In
particular, we analyze how the fixed-point structure of four-fermion
interactions is related to the confining dynamics in the gauge sector. We show
that there exists indeed a mechanism which dynamically locks the chiral phase
transition to the deconfinement phase transition. This mechanism allows us to
determine a window for the values of physical observables in which the two
phase transitions lie close to each other.
