Molecular engineering of electronic materials

Mini-Course I

Manuel de Almeida C2TN

During the last years an increasing number of molecule based materials with unusual electronic properties, complex phase transitions and diverse ground states have been developed. Such properties are associated to strong electronic correlation effects that in molecular systems (organic or inorganic based) are quite sensitive not only to temperature and magnetic field but also to pressure. The molecular and crystalline engineering tools that have been used to develop such materials with emphasis on conducting systems (metals and superconductors) and spin-ladder systems of molecular nature, will be presented in a pedagogical perspective, exemplifying how a diversity of unique physical properties can be obtained.

Topological quantum matter with examples

Mini-Course II

Eduardo Castro (CF-UM-UP) & Miguel Gonçalves (CeFEMA)

As undergraduates, we all learn about metals, insulators, semiconductors, and semimetals. We know how to characterize them and what their differences are. However, not so many years ago, it became apparent that not all insulators are alike. Some, though insulating in the bulk, possess robust metallic states at the boundary and unexpected quantization of certain bulk properties. In this mini-course, by working out specific examples in 1D and 2D, we will explore how to characterize such insulators using concepts borrowed from topology.

Needs: Mathematica

Spinorbitronics based on Topological Insulators

Mini-Course III

Sofia Ferreira Teixeira (IFIMUP)

Spintronics has seen remarkable progress in the last decades. One sub-field that has emerged in recent years is Spinorbitronics, which is one of the developments that has the potential to accelerate the widespread uptake of spintronics, by promoting the development of logic and memory devices. Spinorbitronics is based on the spin to charge interconversion (SCI), exploiting the high spin-orbit coupling (SOC) of certain non-magnetic materials, such as heavy metals, and, more recently, 2D Van der Waals structures. However, a new class of quantum materials, the topological insulators (TIs), which exhibit a metallic topological surface state (TSS), and host spin-momentum locking, could also lead these developments. By combining the TSS properties with their high SOC, outstanding SCI performances can be achieved with TIs.

In this mini-course, the progress towards TIs employment in spintronic devices will be explored from an experimental point of view. The challenges of fabricating TIs materials to extract their properties will be discussed, with an examination of the main techniques currently used. Following these discussions, the study of their properties, mainly transport properties, such as magnetoconductance and Seebeck coefficient, will be addressed, with the main goal of exploring what these techniques can tell us regarding the electronic and spin transport in TIs. The effects employed in the spin to charge interconversion will also be explained, with the focus on how these manifest in TIs. To conclude, the available experimental methods for characterising the SCI will be examined, while also the current progress towards the realization of spinorbitronic devices will be discussed.