Probing Single-Molecule Magnets with Graphene Quantum Dots
Abstract
Title: Single-Molecule Magnets with Graphene Quantum DotsObjective: To use graphene quantum dots to study single-molecule magnets. The quantum dot will work both as highly-sensitive bolometers and as templates to graft molecular magnets. The grafting will be done either with monolayer coverage, for spectroscopy studies of themolecules, or with just a few molecules on each dot, to study how the coupling to the molecules affects quantum transport through a dot, potentially providing a readout of the molecule spin state. Approach: In this project, PI proposes to use graphene quantum dots as templates to graft different single molecular magnets (SMMs) with monolayer thickness. The atomically smooth surface and the capability to tailorappropriate ligands to anchor the molecules to graphene makes it a suitable substrate. In addition, the graphene will not simply be a passive template. The graphene quantum dots will be used as highly sensitive bolometers for spectroscopic studies of these SMM monolayers, to compare the properties of the monolayers to their bulk counterparts. PI will also graft just a few molecules on the quantum dot and study how their interaction with the graphene quantum dotaffects electronic transport through the dot. This study will probe the possibility to use changes in the electrical current through the dot as a non-destructive redout of the magnetic state of the dot. This work will be done using epitaxial graphene on SiC and standard lithography, thereby offering a platform that is fully scalable for practical application.SOW: Specific research tasks are: Task 1. Graphene quantum dots with no gate1.1. Fabrication and THz chacterization of graphenequantum dot bolometers. 1.2. Grafting of SMM monolayers on graphenebolometers. 1.3. Testing and comparison of bolometers with THzradiation and B field.1.4. Ultra-sensitive HF-EPR spectroscopy of SMMmonolayersTask 2. Graphene quantum dots with gate2.1. Fabrication and characterization of gated dots(Coulomb blockade in zero field and B field) 2.2. Bolometric response of gated dots2.3. Characherization of gated dots in B field and THzradiation combined. 2.4. Study of Coulomb blockade vs. B-field and THzradiation.Task 3. Selective grafting (graphene quantumdots with gate)3.1. Lithography for selective grafting (SU8 willcover the whole graphene area except the dot).3.2. Selective grafting of quantum dots with SMM.3.3. Testing of Coulomb blockade in B-field and THzfield for grafted dots and comparison with dots that are not grafted. 3.4. Study of effect of SMM magnetic state onquantum transport.Merit & Relevance: As we start exploring bottom-up atomic precision synthesis of carbon molecular devices and circuits, the spin degree of freedom becomes critically important, possibly even more important than the traditional charge degree of freedom. SMM s are a promising new molecular system, whose spin properties could potentially be exploited for device functionality at molecular and atomic scale.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141612674
Entities
People
- Paola Barbara
Organizations
- Georgetown University
- Office of Naval Research
- United States Navy