Candidate: Gabriel Vinicius De Oliveira Silva
Date: September 3, 2026
Time: 9:00 AM
Location: Online
Supervisor: Guo-Xing Miao
All are welcome!
Abstract:
The development of energy-efficient spintronic technologies requires new approaches for controlling magnetic and electronic states that go beyond the conventional current-driven mechanisms. Among the emerging alternatives, ionic control has attracted significant attention due to its low-voltage operation and its capability to exploit functionalities that are often inaccessible to conventional field-effect approaches. However, the widely used ionic-liquid approaches remain challenging to integrate into scalable device architectures like CMOS technology. In this thesis, a fully solid-state iontronic platform is developed to achieve reversible voltage-driven control of spintronic functionalities through Li-ion motion. Inspired by rechargeable battery technologies, our platform combines a solid-state electrolyte and lithium reservoir for ionic manipulation in a microelectronic-compatible device geometry. The versatility of this approach is demonstrated across multiple material systems relevant to spintronics. First, ionic modulation of Co/CoO heterostructures makes possible reversible control of exchange bias through voltage-driven Li intercalation/deintercalation. The same iontronic architecture is then employed in the topological insulator (Bi1-xSbx)Te3 to dynamically tune the weight between bulk and topological surface-state transport, providing the basis for a valve-like concept in which TSS-associated transport signatures can be modulated on demand. Finally, its implementation in the ferromagnetic metal Cr2Te3 reveals that ionic control can also reconfigure electronic and magnetic ground states, allowing us to access multi-state anomalous Hall polarity switching and magnetic anisotropy tuning. Together, these results establish solid-state iontronics as a versatile framework for controlling magnetic order, topological-associated and Berry-curvature-driven transports within a common device architecture. Our battery-like iontronics platform is a promising pathway that combines low-voltage operation, reversibility, and compatibility with scalable solid-state implementations for programmable and energy-efficient spintronic technologies.