In recent years, spin-orbitronics has highlighted how strategic it is to have materials capable of efficiently converting charge currents into spin currents (and vice versa), because this interconversion is the “engine” behind many low-power device architectures (e.g., concepts based on spin-orbit torque). In this context, Topological Insulators (TIs) represent a particularly promising platform: their surface states with spin-momentum locking can enable highly efficient spin-charge conversion at interfaces, making them ideal candidates for scalable spin-orbitronic devices. To bring these properties into technology, large-area TI films are needed, grown with industrially compatible techniques and integrable on semiconductor substrates (Si/Ge and related platforms), while preserving interface-dependent properties. The goal of this thesis is to develop and characterize large-area TI-based heterostructures and to quantitatively measure their spin-orbitronic functionality through electrical and/or optical protocols, including spin-charge interconversion phenomena and their manifestation as spin-population-induced resistance changes, with a perspective oriented toward the realization of building blocks for spin–orbitronic devices.

The thesis work involves an experimental activity focused on:

1. growth and fabrication of large-area TI/semiconductor heterostructures, with particular attention to quality, stoichiometry, and compatibility with scalable processes;
2. measurements to validate the topological character and spin-orbitronic functionalities at cryogenic temperatures (down to T = 4 K) and under an applied magnetic field;
3. data analysis aimed at extracting device-relevant figures of merit such as spin–charge interconversion efficiency and transport lengths.

The thesis work will be carried out in collaboration between the SemiSpin laboratory of the Department of Physics and the IMM/CNR group at STMicroelectronics in Agrate Brianza, under the supervision of (PoliMi) Prof. Carlo Zucchetti and (CNR) Dr. Roberto Mantovan. Within this framework, the student will:

1. perform cleanroom activities (IMM and Polifab) for device fabrication and characterization;
2. use state-of-the-art instrumentation for magneto-transport measurements to quantify the electrical readout induced by spin signals;
3. gain methodology and autonomy in the critical analysis of results (validation, comparison with the literature, physical interpretation, and proposing improvements).

During the thesis, the skills acquired by the student will not remain confined to the project, but will constitute a solid scientific and professional background, valuable both in academia and for highly qualified positions in the Hi-Tech job market. The expected duration is about 9 months, with flexible yet continuous commitment (compatible with academic requirements). Interested students can contact Prof. Carlo Zucchetti or Dr. Roberto Mantovan.