CANCELLED: Interactions Between Acceptor Pairs in p-Doped Semiconductors

This seminar has been cancelled.

Defects in semiconductors have attracted recent interest as promising candidates for the implementation of qubits for quantum computation and simulation.  In such implementations, controlling two-qubit interactions requires a detailed understanding of the dopant-dopant interaction and its dependence on the separation between dopants.  One of the difficulties associated with donor-based qubits in multivalley semiconductors is that, due to interference between the conduction-band valleys, the donor-donor interaction has a significant  oscillatory component as a function of inter-donor separation.  Acceptor-based qubits lack such multivalley complications but require consideration of a degenerate valence-band maximum and spin-orbit coupling.  In this talk, I will discuss our recent calculations of the acceptor-pair energy spectrum, in both the small-separation regime, for which we have performed a numerical Heitler-London calculation, and the large-separation regime, for which direct electric quadrupolar interactions dominate and we have obtained surprisingly simple and universal results in closed form.  Interestingly, this universality can be traced to the nontrivial vanishing of a particular Wigner 6-j symbol.