Endohedral Fullerene Ti@C28: Single-molecule device for future data storage applications

Under Moore's law, electronic devices have been increasingly miniaturized over the years, leading to issues such as short-channel effects and an extreme increase in power dissipation. At the same time, future miniaturization of solid-state devices could reach the physical limit of scaling, with dimensions comparable to de Broglie's wavelength. To continue to address the increasing demand for miniaturization, high performance, and low power consumption, research efforts moved on technologies called "Beyond CMOS" including molecular electronics, based on the idea of using single molecules as electronic components. Among these molecules, fullerenes are distinguished by their cage-like structures and their capacity to encapsulate atoms or clusters inside. This thesis aims to investigate the possibility of having storage devices using the smallest stable fullerene: C28. The first chapter provides a theoretical background and a review of the state-of-art literature. The second chapter reports an initial study conducted on the stability of the encapsulation of different elements in C28, which leads to the endohedral monometallofullerene Ti@C28 being selected to be investigated through ab initio calculation as a candidate for data storage applications. The encapsulation energies and the electronic properties of two stable states of the Ti@C28 - namely I-Ti@C28 and II-Ti@C28 - were analyzed in the same chapter. In the third chapter, different adsorptions of I-Ti@C28 and II-Ti@C28 onto a gold substrate were simulated to select the most realistic geometries of fullerenes once adsorbed. Using these most probable adsorption configurations and by emulating a Scanning Tunneling Microscope (STM) break-junction experimental setup, the STM-mediated transport characteristics were analyzed. The final chapter summarizes the results of the analyses which show more than 10 μA of current difference between the two stable states when a bias voltage of 1.5 V is applied. This outcome enables binary encoding of the information and therefore establishes the analyzed device as a potential single-molecule data storage element.