Seminaria

Dnia 2024-06-04 o godzinie 13:15 w Sali 2011 Wydziału Fizyki UwB, dr Michał Antkowiak z Zakładu Fizyki Materiałów Funkcjonalnych UAM wygłosi wykład pt:

„Modelling and simulations of molecular nanomagnets”

Serdecznie zapraszamy

Andrzej Maziewski

Jerzy Przeszowski

„Modelling and simulations of molecular nanomagnets”

Michał Antkowiak

Zakład Fizyki Materiałów Funkcjonalnych UAM

Magnetic molecular nanostructures are fascinating subjects of study due to their spectacular quantum properties and envisaged technological applications in computer memory devices and quantum processors. These regular objects serve as testbeds for verifying fundamental quantum theories. Their most promising low-temperature properties crucially depend on their quantum nature, which leads to discrete energy levels. Magnetic molecules, a subclass of the molecular nanostructures, are composed of mutually coupled magnetic ions, forming a single magnetic entity characterized by a spin quantum number S, which labels the energy levels.

The ground state level, the quantum level at the bottom of the energy spectrum, is particularly significant. Ideally, magnetic molecules should exhibit a ground state with either the lowest or highest value of S, depending on the desired application. The ground state of a molecule is determined by its constituent magnetic ions and their interactions. Given the enormous variety of ions and interaction architectures, the chemical synthesis alone may not be optimal for purpose-specific tailoring of these molecules.

Formulation and investigation of the models based on experimental studies of known existing magnetic molecules is the best strategy to indicate potential molecules or systems with improved magnetic properties. The design of molecular nanomagnets can be optimized through computer-aided approach based on the mathematical models that accurately represent real physical molecules. These models must be flexible to account for complex molecular structures, including anisotropy, coupling heterogeneity, and g-factors. Precise determination of the energy structure is crucial for analysing quantum level crossings, interpreting neutron scattering spectra, and assessing ground state stability at low temperatures. Given the complexity of some molecules, supercomputers are often required for these calculations. This presentation explains the use of the exact diagonalization for molecular nanomagnets modelling and showcases selected results obtained using this method.