A Cryogenic Magneto-Optical System for Probing Correlated Physics in Covalent Organic Frameworks
Abstract
The purpose of this proposal is to acquire a closed cycle superconducting magnet and microscopy optical cryostat that will be integrated with existing tunable femtosecond lasers to create a new cryogenic magento-optical system for probing correlated physics in covalent organic frameworks (COFs). The closed-cycle superconducting magnet provides a magnetic field up to 9 tesla with low vibration, and the microscopy optical cryostat allows for sample cooling down to 4 Kelvin within the magnetic field. Coupled with the tunable femtosecond lasers, the cryogenic magneto-optical system offers the capability to perform broadband optical micro-spectroscopy and ultrafast pump-probe spectroscopy at different magnetic field strengths. We will utilize this new magneto-optical system to further the goals of our DoD MURI project entitled ÒCenter for Advanced 2D Organic Networks (CATON)Ó which is focused on developing new 2D covalent organic network and explore their novel physical and chemical properties. Many fascinating quantum phenomena arise from the competition between the kinetic and potential energy. In particular, strongly correlated behaviors ranging from magnetism to fractional quantum hall states can appear when the kinetic energy is strongly suppressed such as in flat electronic bands. Recent theoretical studies of our MURI team identified novel 2D covalent organic frameworks (COFs) exhibiting a flat electronic band. With strongly enhanced electron-electron interactions in 2D materials, such flat electronic band provides exciting opportunity to explore strongly correlated physics and magnetism in 2D COFs. The new magneto-optical system will enable the first experimental study of flat-band magnetism and correlated phenomena arising from strong correlation in 2D COFs. We will additionally explore magnetism in the heterostructure of 2D COFs and transition metal dichalcogenides (TMDCs), where the flatband magnetism of COF can couple to the spin-valley degree of freedom in TMDCs. Students and postdocs at all levels will be exposed to cutting-edge optical spectroscopy and 2D COF materials, and will learn how to develop new experimental probes and to interpret new forms of data relevant to understanding nanoscale electronic, magnetic, and optical behavior, as well as being schooled in how to deliver effective presentations and write impactful journal articles.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810225
Entities
People
- Feng Wang
Organizations
- Army Contracting Command
- United States Army
- University of California, Berkeley