Spin-resolved imaging and spectroscopy of individual molecules with sub-molecular spatial resolution
- PDF / 545,080 Bytes
- 6 Pages / 585 x 783 pts Page_size
- 40 Downloads / 183 Views
Introduction: Molecular electronics Component miniaturization in the semiconductor industry has been remarkable and has even outperformed the ambitious predictions put forth by Moore’s law, which states that the number of transistors per integrated circuit doubles every two years. Molecular electronics stems from the idea of performing the basic functions of electronics—rectification, amplification, and storage—with few or even single molecules embedded between electrodes.1 Indeed, rapid progress in both the understanding and experimental realization of molecular devices has been achieved.2 In optoelectronics, organic lightemitting diodes as well as organic photovoltaics have found their way into the marketplace and are competing with conventional semiconductor technology today. Nonetheless, inorganic semiconductor electronics is the current benchmark: transistors available in the market are as small as 22 nm, and a reduction down to 5 nm is technologically within reach already. These are dimensions that are comparable to many single molecules that were envisioned to replace their inorganic counterparts, provoking the question of whether the original promise of organic molecular electronics can still be fulfilled. Molecule-based devices show potential in a new field within electronics that not only uses the charge of the electron but also uses its spin (e.g., to store data or perform computations).
The area of research that addresses the question of how spins can be injected, manipulated, and detected in the solid state is collectively referred to as spintronics (see the Introductory article in this issue). Recent pioneering experiments and theoretical studies suggest that organic materials can offer similar or even superior performance in spin-based devices compared to their inorganic metallic or semiconducting counterparts.3 Experiments on spin transport through break junctions4 and spin valves5,6 (see the article by Nguyen et al. in this issue) have unveiled exciting new frontiers of molecular magnetism. In particular, single molecule magnets are, if deposited on appropriate electrodes, a viable route toward quantum computing.7–9 However, in order to understand the processes determining the spin-dependent characteristics of organic systems in contact with a ferromagnetic (FM) electrode, microscopic insights into interface properties, including information on the local spin-resolved transport through single molecules, is required. Spin-polarized scanning tunneling microscopy (SP-STM) is a tool that can address these fundamental issues.10
Local spin-resolved experiments on single molecules on surfaces Experiments on organic semiconductors (OSCs) have revealed substantial spin relaxation times and significant spin diffusion
Jens Brede, Institute of Applied Physics and Interdisciplinary Nanoscience Center Hamburg, University of Hamburg, Germany; [email protected] Roland Wiesendanger, Department of Physics, University of Hamburg, Germany; [email protected] DOI: 10.1557/mrs.2014.127
608
M
Data Loading...
