Institut des
NanoSciences de Paris

1D/3D self-assembly of molecules on crystal surfaces : electronic and magnetic properties

Nadine Witkowski

Over the past decade, the emergence of molecular electronics has opened up interesting perspectives in the development of sensors, transmitters, switches or memory storage. Molecular electronics promises lower production costs than traditional semiconductor electronics and reduced energy consumption. In addition, the wide variety of molecules available or potentially allows application flexibility and enhanced potential. Among these molecules, phthalocyanines, are ideal candidates because they are very chemically and thermally stable, and they can accomodate in their center a magnetic ion offering easy tunable magnetic properties. In this project, we will study and will understand how these magnetic molecules interact with different types of substrates, either at individual or collective level.

The first step of the project consist in preparing thin films based on magnetic phthalocyanines (low spin / high spin phthalocyanines) on different superconducting surfaces under ultra-high vacuum conditions. Structural characterizations of the films will be achieved in situ by standard surface techniques (LEED, Auger, surface sensitive optical reflectivity) by surface diffraction techniques and near-field microscopy. The magnetic properties will be studied in a second step by X dichroic absorption techniques and photoemission dichroic (valence band and levels cores) on synchrotron radiation, and also by STS at ultra-low temperature (300 mK) and under high magnetic field.

We will focus on the interaction between the single molecular magnet and the superconducting state that can also compete with Kondo type of behavior. Ultimately we hope to link the molecules to make a 1D chain of magnetic molecules that could lead to new electronic states type Majorana fermions.


The project corresponds to Danilo Longo’s thesis under joint supervision with Tristan Cren and Cristophe Brun from the team Spectroscopy of Novel Quantum States