Suppression of Coulomb exchange energy in quasi-two-dimensional hole systems

We have calculated the exchange-energy contribution to the total energy of quasi-two-dimensional hole systems realized by a hard-wall quantum-well confinement of valence-band states in typical semiconductors. The magnitude of the exchange energy turns out to be suppressed from the value expected for analogous conduction-band systems whenever the mixing between heavy-hole and light-hole components is strong. Our results are obtained using a very general formalism for calculating the exchange energy of many-particle systems where single-particle states are spinors. We have applied this formalism to obtain analytical results for spin-3/2 hole systems in limiting cases.