Fabrication, characterization, and mechanical loading of Si/Si-Ge membranes for spin-qubit devices
Year: 2025
Type: article
Abstract: Si / Si Ge heterostructures on bulk Si substrates have been shown to host high-fidelity electron spin qubits. Building a scalable quantum processor would, however, benefit from further improvement of critical material properties such as the valley-splitting landscape. Flexible control of the strain field and the out-of-plane electric field E z may be decisive for valley-splitting enhancement in the presence of alloy disorder. We envision the Si / Si Ge membrane as a versatile scientific platform for investigating intervalley scattering mechanisms which have thus far remained elusive in conventional Si / Si Ge heterostructures and have the potential to yield favorable valley-splitting distributions. Here, we report the fabrication of locally etched, suspended Si Ge / Si / Si Ge membranes from two different heterostructures and apply the process to realize a spin-qubit shuttling device on a membrane for future valley mapping experiments. The membranes have a thickness in the micrometer range and can be metallized to form a back-gate contact for extended control over the electric field. To probe their elastic properties, the membranes are stressed by loading with a profilometer stylus at room temperature. We distinguish between linear elastic and buckling modes, each offering mechanisms through which strain can be coupled to spin qubits.
Source: Physical Review Applied
DOI: 10.1103/rw7k-pcvw
Authors: Lucas Marcogliese, Ouviyan Sabapathy, Rudolf Richter, Jhih-Sian Tu, Dominique Bougeard, Lars R. Schreiber
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W4417174603