Thesis projects:
ab initio ELECTRONIC STRUCTURE AND SPECTROSCOPY

Ab initio modeling and characterization of novel 2D carbon materials (MSc)

Supervisor: Dr. Simona Achilli (simona.achilli@unimi.it)

Description: 2D carbon networks combining atoms with sp- and sp2- hybridization represent nowadays a promising class of novel materials beyond graphene, with perspective of application in many fields (electronics, energy conversion….).

These systems can be obtained via the assembly of organic molecules on a metal surface through a multi-step, temperature-dependent process. The final geometry of the network, dictated by the choice of the molecular precursors, influences the properties of the material that are also sensitive to the interaction with the supporting substrate.

The project aims to understand the structure-property relationship of 2D carbon networks via ab initio simulations in the framework of the Density Functional Theory.

The student will be asked to learn an ab initio computational code and simulate 2D networks  to face one of these aspects:

• Mechanism of growth: calculation of reaction paths of molecular precursors on the metal surface 

• Detailed characterization of structural and electronic properties of 2D networks and effects of the substrate

• Quantum transport in lateral heterojunction: calculation of the electronic current flowing through 2D carbon networks laterally connected (Non Equilibrium Green's function techniques).

Expected duration: 7/8 months

Ab initio modeling of defects for quantum technologies (MSc)

Supervisor: Dr. Simona Achilli (simona.achilli@unimi.it)

Description: Single point defects in semiconductors and 2D materials have been envisioned as suitable solid-state systems for applications in future quantum technologies. Ab initio theoretical calculations can provide useful insight for their complete characterization, also supporting and guiding experiments.

The student will be asked to learn an ab initio computational code based on Density Functional Theory and simulate defects as magnetic atoms in 2D materials (ex. hBN or graphene), dopant atoms or aggregates in silicon. Starting from an initial assesment of the defect stoichiometry, structure and stability of the defect, the project will focus on the characterization of the ground-state and excited-state properties.

Expected duration: 7/8 months

Theoretical study of molecule-antiferromagnet interfaces (MSc / BSc)

Supervisor: Prof. Guido Fratesi (guido.fratesi@unimi.it)

Description: Antiferromagnets are promising materials for application in spintronics devices with several advantages over conventional ferromagnets (high-frequency response, long spin propagation, etc). Organic molecular layers at their surface allow tuning their magnetic properties (e.g., by magnetic hardening), and is expected to bring new functionalities such as coupling to light.

Our research aims to the prediction of the structural, electronic, magnetic and optical properties of the systems, concerning in particular the hybridization between the organic molecules and the antiferromagnetic substrate, and exploring different possible combinations of substrates, molecules and interfaces.

The thesis project aims to investigate the interaction between an organic molecule and the surface of an antiferromagnetic oxide (e.g., CoO, Fe2O3, …) determining the structure and magnetic configuration of the interface. These materials require a theoretical treatment beyond the standard single-electron approach that will be tackled by the inclusion of many-body terms to the Hamiltonian.

The student is expected to learn one of the most diffuse ab initio computational packages and to apply it to the molecule/interface focusing on:

• Determination of the system structure and its electronic/magnetic properties.

• Numerical treatment of the many-body terms in the computational package.

Expected duration: 7/8 months (MSc) 2/3 months (BSc)

Testing the implementation of Zeeman effect in the SIESTA code(BSc)

Supervisor: Dr. Simona Achilli (simona.achilli@unimi.it)

Description: Applying a Zeeman magnetic field to the spins in a solid allows to have access to the linear magnetic susceptibility tensor and the linear magnetoelectric tensor. A recent implementation of this effect, realized through an effective additional potential acting on the spin density, has been recently realized in the Density Functional based code SIESTA. The student will be asked to test the implementation by running calculations in SIESTA for selected cases studying the effect of the magnetic field on the electronic structure of solid-state systems. The comparison of the results with those obtainable with other ab inito codes will allow to refine and check the new module and to include it in the future released version of the code.

Expected duration: 2/3 months

Contact us for the fine tuning of these and other possible thesis projects