This is a past event.

Juan E. Peralta from Central Michigan University will present at this week's Physics Colloquium.

Peralta's presentation is titled "Molecular Magnetism from Density Functional Theory."

The seminar will be presented in person at 4 p.m. on Thursday (Sep. 12) in Fisher 139.

*This talk is made possible through the generous support of the Vasant R Potnis Physics Fund.

ABSTRACT:

Molecular magnetism has received renewed attention due to the potential of using molecular spins in diverse applications such as quantum computing, data storage, spintronics, and quantum sensing. For all practical applications, it is of fundamental importance to devise predictive computational tools that help us understand the underlying phenomena at work, like magnetic anisotropy and exchange couplings, magnetic relaxation, or quantum effects. From its early days, density functional theory (DFT) became a workhorse for predicting the magnetic properties of molecules and materials. In this talk, I will review some of the aspects of DFT applied to problems that involve magnetism, show some methods that we have developed over the years, [1-3] and illustrate these ideas with two examples from our recent work. The first example is for a set of large multi-center transition metal complexes, where magnetic exchange couplings cannot be established through experimental methods. In this case, DFT provides the only option to determine these properties without empirical data. I will show our recent results for multi-nuclear Fe complexes recently synthesized by our collaborators, including the largest molecular ferric wheel at present. [4,5] The second example is related to mechanically controllable break-junction experiments. Using this technique, our experimental collaborators showed that the magnitude and orientation of applied magnetic fields can be used to control the fundamental structural properties of atomic wires. With the help of DFT calculations, we developed a model that explains the results of these experiments and validates the basic hypothesis.[6] We were able to show that the tension developed at the edge atoms in a Pt junction depends on the overall wire magnetization orientation. This tension proves to be critical in determining the wire elongation points, at which the number of atoms in the wire increases, a key ingredient to explain the experimental observations.

[1] J. Chem. Phys. 129, 194107 (2008); [2] J. Chem. Theory Comput. 8, 3147 (2012); [3] J. Phys. Chem. A 126, 6790 (2022); [4] Inorg. Chem. 61, 17256 (2022); [5] Inorg. Chem. 61, 11261 (2022); [6] Nat. Commun. 13, 4113 (2022)

BIO:

Prof. Peralta is a Professor of Physics at Central Michigan University. After earning his Ph.D. in Physics from the University of Buenos Aires, he joined Rice University as a postdoctoral fellow before moving to Central Michigan University. His research interests include molecular magnetism, computational methods involving density functional theory, and addressing self-interaction error. His research group is well-supported by grants from the NSF and DOE. Additionally, he is the recipient of the President’s Award for Outstanding Research and Creative Activity at Central Michigan University.