Study of synthesis mechanism of complex layered magnetic quantum materials

Computational materials design has been playing an important role in discovering novel quantum materials such as topological materials. One of the major challenges in synthesizing computationally designed materials is that their thermodynamic stabilities are often unknown, which significantly reduces the rate of successful synthesis. Therefore, thermodynamic stability predictions for computationally designed materials are key to accelerate new quantum material discoveries. For complex quantum materials such as the ternary layered magnetic materials proposed in this project, their thermodynamic stability predictions are challenging, since this type of materials not only involves different kinds of chemical bonds ranging from the in-plane strong covalent bonds to weak interlayer van der Waals interactions, but also needs accurate treatments of thermal excitations from electronic, vibrational, and magnetic degrees of freedom, which makes first-principles-based thermodynamics calculations difficult.

This proposed research aims to address this challenge through the integrated experimental and theoretical investigations of the synthesis mechanisms of two types of ternary layered magnetic quantum materials which are recently predicted to host a rich variety of new quantum states. Most members of these two material families are hypothetical, with unknown thermodynamic stability. The PIs will perform synergistically computational and experimental synthesis of the proposed materials. The co-PI Sun's group will predict their thermodynamic stability through first-principles-based free energy calculations. The single crystal growth of the proposed materials by the Mao group will be guided by the stability predictions from the Sun group. For those successfully synthesized materials, Mao will perform detailed experimental studies, including crystal structure and spin structure determinations and thermodynamic quantity measurements. The data obtained from these experiments will provide feedback to theoretical calculations, which can not only validate the theoretical models, but also enable theoretical method improvements. Through these efforts, the PIs anticipate making the synthesis of complex layered quantum materials more predictive.