Measurement and Ab Initio Calculation of Quantum Conductance and Electronic Properties of Lower Diamondoid Molecules and Derivatives
Y. Xue, G. Ali Mansoori, L. Assoufid
University of Illinois at Chicago, US
Keywords: ab initio, adamantane, AFM, amantadine, diamantane, diamondoids, electronic properties, HOMO, LUMO, memantine, NEMS, quantum conductance, rimantadine, SPM, STM, transmission spectrum
Abstract:Diamondoids and their derivatives have found major applications as templates and as molecular building blocks in nanotechnology. Applying ab initio and experimental methods, we have been calculating and measuring the quantum conductance and the essential electronic properties of two lower diamondoids (adamantane and diamantane) and three of their important derivatives (amantadine, memantine and rimantadine). We are also studying two artificial molecules that are built by substituting one hydrogen ion with one sodium ion in both adamantane and diamantane molecules. Our measurements are based on using scanning probe microscopy (STM & AFM) and our calculations are based on an infinite Au two-probe system constructed by ATK and VNL software, which comprise TRANSTA-C package. By changing various system structures and molecule orientations in linear Au and 2_2 Au probe systems, we found that although the conductance of adamantane and diamantane are very small, the derivatives of the lower diamondoids have considerable conductance at specific orientations and also showed interesting electronic properties. The quantum conductance of such molecules will change significantly by changing the orientations of the molecules, which approves that residues like nitrogen and sodium atoms have great effects on the conductance and electronic properties of single molecule. There are obvious peaks near Fermi energy in the transmission spectrums of artificial molecules, indicating the plateaus in I-V characteristics of such molecules.