This award supports research and education in theoretical and computational condensed matter physics to offer insight into the coexistence of quantum phases at the nanoscale and the possible emergence of new quantum phases. The project focuses on hybrid nanostructures made of a superconducting material in proximity with either inhomogeneous magnetic materials or a graphene multilayer. These systems are of interest for building novel electronic and spintronic devices.
In the case of superconducting-magnetic heterostructures, the magnetic inhomogeneities considered are tunable domain walls. The merit of the particular model-system lies in the ability to tune continuously the influence of the inhomogeneity through the application of a weak external perturbation. This offers a unique opportunity to understand within one and the same probe how inhomogeneities affect the state of the system. It leads to a consistent unified picture of coexisting phases in superconducting-magnetic nanostructures that are experimentally realizable. Particular emphasis will be placed on magnetic Josephson junctions incorporating the tunable domain wall in the clean limit for their potential to be used as building blocks for novel devices. Both static and dynamic equilibrium properties will be studied under the application of external perturbations.
In graphene-based hybrid structures the main tuning parameter is the finite but arbitrary number of graphene sheets. The stacking of individual graphene layers affects dramatically the single-electron and the electronic collective modes of the structure. The tuning of the hybrid nanostructure will allow a better understanding of these collective modes, charge screening properties and superconductivity in layered materials. The analysis of hybrid nanostructures will also be extended to the newly discovered topological insulators and superconductors.
The award supports the PI's educational activities through the training of Master's and undergraduate students in performing research in condensed matter theory, presenting results through talks at conferences and the writing of peer-reviewed publications and Master's theses. The award will contribute to the development of a strong and solid Master's program that serves the community by offering practical training and problem solving skills for those entering the workforce and by being a bridge from the undergraduate degree to PhD programs across the nation, one that is traditionally inclusive of groups of the population that are underrepresented in materials research.
NONTECHNICAL SUMMARY
The award supports research and education in theoretical and computational condensed matter physics in a primarily undergraduate institution. The project is devoted to the study of coexisting phases of matter at the nanoscale. The purpose of the study is to better understand the behavior of electrons at these scales when materials with different ground states are in contact. Understanding at the fundamental level how phases mingle in a heterostructure will allow harnessing the physical properties of these systems and offer avenues to develop new electronic and spintronic devices, for example in the areas of sensors or quantum computing.
This study will focus on nanostructures made of layers of different materials. These hybrid nanostructures exhibit a variety of peculiar properties and phases. Emphasis is placed on layered systems composed of alternating superconducting thin films and thin films made of familiar magnetic materials. In superconductors, electrons form an organized state of stable pairs that can conduct electricity without loss. Electrons in the heterostructures can 'tunnel' from one material through the other and are exposed to very different interactions along the way. The goal of project is to describe how electrons organize themselves in these different environments as they travel among the layers.
The PI will also study novel heterostructures where the magnetic system is replaced with recently discovered novel materials. For example, the PI will incorporate graphene multilayers and nanoribbons, and topological insulators into the structure. These systems have rather different properties and electronic organization, and the PI aims to understand effects of these different materials.
The award supports the PI's educational activities through the training of Master's and undergraduate students in performing research in condensed matter theory, presenting results through talks at conferences and the writing of peer-reviewed publications and Master's theses. The award will contribute to the development of a strong and solid Master's program that serves the community by offering practical training and problem solving skills for those entering the workforce and by being a bridge from the undergraduate degree to PhD programs across the nation, one that is traditionally inclusive of groups of the population that are underrepresented in physics.
