Flux control in a three-site Kitaev chain in coupled quantum dots

Majorana bounds states (MBSs) can be engineered in semiconductor-superconductor hybrids by realizing a Kitaev chain. We study a three-site Kitaev chain in a semiconductor two-dimensional electron gas, where we couple three QDs via two hybrid regions. In this configuration the control over the relative superconducting phase between the two hybrids becomes crucial, as a π-phase difference is expected to close the gap between MBSs and higher energy excitations. To address this, we drive a flux through a superconducting loop connecting the two hybrid regions and study the dependence of the density of states through tunnelling spectroscopy measurements at all three QD sites. The study provides important insights for controlling longer Kitaev chains, providing a step forward towards integrating robust MBS-based qubits.