Non-technical Abstract: This project, which is supported by the Solid State and Materials Chemistry and Condensed Matter Physics programs of the Division of Materials Research, puts forward a systematic way to synthesize a new class of quantum materials named magnetic topological semimetals. These materials are characterized by a small concentration of highly mobile electrons with polarized magnetic moments. As a result of the small concentration and the high mobility of these polarized electrons, quantum effects can be observed at low magnetic fields and moderate temperatures within the reach of most small laboratories. The main quantum effect in the magnetic topological semimetals is that their magnetic order determines their electrical conduction and vice versa. Therefore, they can act as magnetic switches, memories, or sensors capable of operating at very small magnetic fields and moderate temperatures which is the most useful range for applications. The project relies on a feedback loop between theoretical calculations, materials synthesis, and characterizations through a combination of chemistry, physics, and materials science techniques. The cross-disciplinary nature of this project provides a unique educational platform for young scientists, from postdocs to graduate and undergraduate students. A new interdisciplinary course is designed by the PI to teach the chemistry and the physics of novel quantum materials to graduate students from both disciplines. The PI makes a conscious effort to connect his research to the society by presenting public lectures and demonstrations at several libraries to explain the physics and the chemistry of materials to the general public.
While most of the current studies on topological semimetals are focused on non-magnetic intermetallic compounds, the PI wants to deliberately take a different trajectory to look at the magnetic compounds with topological potentials. The materials explorations in this project exploit recent advances in the theoretical classification of topological systems based on the crystalline and the time reversal symmetries. The impact of the project is to open a new direction in topological materials design by incorporating magnetism with Dirac/Weyl physics in a systematic way. The project is particularly timely due to the rapid advances in the field of non-magnetic semimetals. The final goal is to engineer novel electronic phases such as chiral conductors which are stabilized by the internal molecular field of the material without the need for an external magnetic field. The project relies on a feedback loop between material synthesis, x-ray crystallography, physical measurements, electron microscopy, and DFT calculations to identify materials candidates, to grow high quality single crystals, and to thoroughly characterize them. The interdisciplinary environment of the PI's lab provides a unique educational environment from undergraduate to postdoctoral level. Connected to this research, a new course titled "from bonds to bands" is developed by the PI for both physics and chemistry graduate students to demonstrate the formation of extended solids from bonding between atoms and molecules.
