This award supports theoretical and computational research aimed at understanding the relationship between experimental measurements and numerical simulations of materials in which strong electronic correlation effects are important. In particular, the team will focus on obtaining computational data simulating the response to externally applied fields in superconducting and magnetic materials.
Materials consist of electrons and ions arranged in a crystal lattice. In some materials, the motion of an electron is strongly interdependent on, or correlated with, the motion of many other electrons. As a consequence, these materials may exhibit unusual behavior including superconductivity, magnetism, or charge order. This unusual behavior can often be investigated with experimental probes that measure the response of a material to externally applied fields. Our standard analytical tools for describing this response are inadequate, and numerical methods are therefore needed. The subject of this project is the development and application of accurate and controlled numerical methods that can describe these materials and their response to applied fields, and compute experimentally measured quantities.
The project will contribute to broader impacts by supporting the development and maintenance of sustainable open-source community software libraries, which will accelerate the development of future codes as well as provide reliable and state-of-the-art applications to the science community. The software libraries currently maintained by the PI are among the few established open-source libraries for calculations on strongly correlated systems. As part of the project, graduate students will be trained in modern theoretical techniques and in scientific software development.
This project is aimed at understanding the relation between experimentally measured two-particle response functions and generalized susceptibilities of effective low-energy lattice models in systems where strong electronic correlations are important, and in particular systems where superconducting or magnetic order has been established. The project will combine newly developed numerical methods with large-scale calculations to compute emergent fluctuations, as well as the response functions measured in superconducting, charge ordered, and magnetic systems.
Susceptibilities reveal important information about collective excitations of a system and are directly measurable in experiment. However, the strong correlation physics of generalized susceptibilities measured by two-particle probes such as neutron scattering is theoretically not well understood, especially in ordered phases. This project will analyze two-particle correlation functions in fermion lattice model systems inside and outside the superconducting phase. By providing reliable results for the susceptibilities of fermionic lattice models and by computing response functions, this work will facilitate the separation of true electron correlation physics from model-dependent artifacts, which in turn will aid in the interpretation of experiments.
Correlated electron materials are essential for modern technological applications such as information technology, energy technology, materials science, and nanoscience. By clarifying the basic behavior of susceptibilities and their relation to experimental work, this project will contribute to our understanding of correlated materials and their characterization.
The project will contribute to broader impacts by supporting the development and maintenance of sustainable open-source community software libraries, which will accelerate the development of future codes as well as provide reliable and state-of-the-art applications to the science community. The software libraries currently maintained by the PI are among the few established open-source libraries for calculations on strongly correlated systems. As part of the project, graduate students will be trained in modern theoretical techniques and scientific software development.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
