Exploring Tunable Strong Electron Correlations in Rare-Earth Molecular Materials Himanshu Gupta

Format:

Book

Thesis/Dissertation

Author/Creator:

Gupta, Himanshu, author.

Contributor:

University of Pennsylvania. Chemistry., degree granting institution.

Language:

English

Subjects (All):

0431.

0488.

0794.

Local Subjects:

0431.

0488.

0794.

Physical Description:

1 electronic resource (293 pages)

Contained In:

Dissertations Abstracts International 87-07B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

Materials comprising localized f-electrons and itinerant conduction electrons are known to show strong electron correlations and heavy fermion physics. Many rare-earth intermetallic materials, such as YbAl3, YbCuIn4, and CeCoIn5, show such rich electronic and magnetic behavior due to partially filled f-orbitals and their subtle interplay with itinerant electrons. Molecular materials represent a promising platform to explore and extend these quantum phenomena within the tunable framework of coordination chemistry. The 2025 Nobel Prize in chemistry highlights this vision by celebrating the potential impact of molecular design to yield novel structural frameworks and functional molecular materials. This dissertation is focused on the synthesis, crystallization, and electronic structure studies of rare-earth molecular materials (particularly with cerium and ytterbium) and probes changes in physical properties by external stimuli. Chapter 2 establishes metal-ligand redox cooperativity as a tool to create mixed-valent lanthanide compounds. Reduction of tetracyanoquinodimethane (TCNQ) by organocerium(III) compound leads to the trapped-valent tetramer through ligand to metal charge transfer. Building on this idea, a light-responsive material with cerium and dibenzotetrathiafulvalene (DBTTF) is presented in Chapter 3. In this material, photo-induced charge transfer reversibly modulates the conductivity and magnetization, providing a platform for rare-earth molecular materials to be used as switchable materials. Metal-ligand redox cooperativity is also operative in the case of ytterbium-based molecular material described in chapters 4 and 5. The combination of organic electron acceptors, pyrazine, bipyridines, and fullerene with organoytterbium(II) compound leads to the formation of a range of molecular materials with strong magnetic exchange and partial electron delocalization. Overall, these findings demonstrate how molecular design principles enable control over electron correlation and external stimuli effects in rare-earth molecular materials. With the combination of synthetic inorganic chemistry, spectroscopy, magnetometry, transport measurements, and theoretical insights, this dissertation advances the development of tunable molecular analogs of strongly correlated quantum materials

Notes:

Advisors: Schelter, Eric J. Committee members: Mallouk, Thomas E.; Murray, Christopher B.; Tomson, Neil C.

Source: Dissertations Abstracts International, Volume: 87-07, Section: B.

Ph.D. University of Pennsylvania 2025

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798276006123

Access Restriction:

Restricted for use by site license