Single-Molecule Electret: a long-sought-after nanoscale component

The miniaturization of modern electronic devices has been approaching the nanoscale. This trend has led researchers to study and develop of single-molecule devices (SMDs), where molecules are employed as active components. Among these molecules, fullerenes and their derivatives distinguish for their distinctive cage-like structures. A single-molecule electret (SME) is a long-desired nanoscale component since it can conduct us to new small storage device with the feature of non-volatile memory. Its main attribute is the switching between two different states by means of an external electric field. Recent studies report a single-molecule electret device based on an endhoedral metallofullerene, demonstrating memory capabilities. The existence of two distinguishable energetic stable states of the Gadolinium (Gd) encapsulated into the C82 fullerene plays a vital role in exploiting Gd@C82 as a memory component. They correspond to two different spatial arrangement of the Gd atom inside the C82. This master thesis starts with the creation of the Gd@C82 molecule with the purpose to test its behavior considering the changes on the different properties with the encapsulation of the Gd atom in the cage C82. This has been done analyzing two different stable positions, taking into account the considerations made in literature. These steps are realized with the use of ATK tool and the tool ORCA for the optimization of the geometry. The second part focuses on the device level. Three different devices are analyzed and compared. The Gd@C82 molecule in the two different configurations (namely I and IV) corresponding to different Gd atom spatial sites are placed between two bulky gold electrode. Their electron structure and transport properties are studied and compared to the reference configuration constituted by the empty C82 cage placed between gold electrodes. With these steps, it could be possible to understand how the presence of the Gd atom perturbs the C82 cage and how its position changes the behavior of the entire device including the resulting transmission spectra and IV curves. In conclusion, the differences in the current magnitude monitored at the electrodes in the two different configurations (I and IV) reveal two different stable logical states, demonstrating the single-molecule electret as promising candidate for future technology for storage applications.