Electrons in surface acoustic waves as spin qubits

PhD Program

Speaker

Mikel Olano

When

2025/10/30
11:00

Place

"Salón de grados" in the Psychology Faculty, EHU, Donostia / San Sebastián

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PhD Thesis defense by Mikel Olano

Supervisor: Geza Giedke (DIPC, Ikerbasque Research Professor)

Solid state coupled quantum dots (QDs) have been long proposed as a platform to control spin qubits and perform quantum computation. One of the most popular methods to create these arrays consists in creating a two-dimensional electron gas (2DEG) in the junction between two semiconductors with a similar band gap, being able to create electron depleted zones by applying electrical voltages with controlled gates. As a possible solution to the short range interactions that can usually be obtained in these scenarios “flying” qubits have been proposed to transport electrons while performing the one and two-particle interactions. Surface acoustic waves (SAWs), which can be created by interdigital transducers (IDTs) in the surface of a piezoelectric material, have been proposed and demonstrated as the carriers of single electrons.

This Thesis covers the main interactions in the transport of single electrons from static to moving dots, including the spin-orbit interaction and the possible spin-flip processes that may happen due to the hyperfine interaction between the nuclear spin bath present in GaAs and the electron’s spin. The numerical analysis of the transfer process shows the possibility of treating the evolution of the system with few low-energy states, which reduces the number of terms to be taken into account to describe and optimize it. At the end, the Coulomb interaction between two particles in different dots is briefly discussed, mainly through the theoretical expressions that enter in its definition and a numerical approximation
for a particular impact parameter.