The search for new paradigms for a spin liquid state in organic based materials

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Non-technical abstract: Some magnets have become a part of our everyday life, but research in new magnetic materials is aimed on discovering magnets showing new unexplored phenomena. Exotic properties, such as quantum disordered magnetic states, are of fundamental interest, but also could be used in new technologies. While a stereotype of a magnetic material is an inorganic compound, this research is aimed on organic magnets. The activities include identifying new organic magnets and understanding how to tune magnetism in them with such external stimuli as pressure. This program shows how to study and control magnetism through its interaction with light. This research involves training of students of various levels, both graduate and undergraduate is carried out. A focus is a support of women interested in STEM. The PI and her group members are involved in community outreach activities, such he Open House Day in the Department of Physics and Astronomy. Technical abstract: This is a proposal to discover and study new paradigms for spin liquid state. A large effort of the community to find this state of matter is primarily dedicated to inorganic materials. In contrast, this work is focused on organic materials, inspired by the fact that they have already produced large number of spin liquid candidates with S=1/2 on triangular lattice. The current research goes beyond that state, exploring a possibility of a spin liquid state driven by coupling to fluctuating electric dipoles in a quantum paraelectric (quantum dipole liquid). Within this proposal the PI plans to test a hypothesis that quantum dipole liquid materials can be tuned into a ``simple'' Mott insulating state with S=1/2 on triangular lattice by a change in the electronic orbital overlap within molecular dimer units. New paradigm in terms of materials will be a study of magnetic metal-organic frameworks, where magnetic metal atoms or clusters are connected by organic linkers into two- or three-dimensional networks. Theory predicts that these materials with frustrated lattice of metal clusters can produce spin liquid and Kitaev spin liquid state. In this proposal, Raman scattering spectroscopy will be used as the main tool to discover new material properties and to understand the driving interactions. 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.