scholarly journals Can One Define the Conductance of Amino Acids?

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 580 ◽  
Author(s):  
Zotti ◽  
Bednarz ◽  
Hurtado-Gallego ◽  
Cabosart ◽  
Rubio-Bollinger ◽  
...  
Keyword(s):  
Amino Acids ◽  
Conformational Changes ◽  
Scanning Tunneling Microscope ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Tunneling Microscope ◽  
Electron Transport Properties ◽  
Recognition Tunneling ◽  
Conductance Distribution ◽  
Statistical Clustering

We studied the electron-transport properties of ten different amino acids and one dimer (di-methionine) using the mechanically controlled break-junction (MCBJ) technique. For methionine and cysteine, additional measurements were performed with the scanning tunneling microscope break-junction (STM-BJ) technique. By means of a statistical clustering technique, we identified several conductance groups for each of the molecules considered. Ab initio calculations revealed that the observed broad conductance distribution stems from the possibility of various binding geometries which can be formed during stretching combined with a multitude of possible conformational changes. The results suggest that it would be helpful to explore different experimental techniques such as recognition tunneling and conditions to help identify the nature of amino-acid-based junctions even further, for example, with the goal to establish a firm platform for their unambiguous recognition by tunneling break-junction experiments.

scholarly journals Solvent-dependent conductance decay constants in single cluster junctions

2016 ◽  
Vol 7 (4) ◽  
pp. 2701-2705 ◽  
Author(s):  
Bonnie Choi ◽  
Brian Capozzi ◽  
Seokhoon Ahn ◽  
Ari Turkiewicz ◽  
Giacomo Lovat ◽  
...  
Keyword(s):  
Scanning Tunneling Microscope ◽  
Electrical Transport ◽  
Molecular Clusters ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Metal Chalcogenide ◽  
Tunneling Microscope ◽  
Decay Constants ◽  
Single Cluster

We study single cluster electrical transport in a series of metal chalcogenide molecular clusters using scanning tunneling microscope-based break-junction measurements.

scholarly journals Enhanced coupling through π-stacking in imidazole-based molecular junctions

2019 ◽  
Vol 10 (43) ◽  
pp. 9998-10002 ◽  
Author(s):  
Tianren Fu ◽  
Shanelle Smith ◽  
María Camarasa-Gómez ◽  
Xiaofang Yu ◽  
Jiayi Xue ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Density Functional ◽  
Molecular Junctions ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Functional Theory ◽  
Tunneling Microscope ◽  
Single Molecule Junctions

We demonstrate that imidazole based π–π stacked dimers form strong and efficient conductance pathways in single-molecule junctions using the scanning-tunneling microscope-break junction (STM-BJ) technique and density functional theory-based calculations.

scholarly journals Connectivity dependent thermopower of bridged biphenyl molecules in single-molecule junctions

Nanoscale ◽  
2020 ◽  
Vol 12 (27) ◽  
pp. 14682-14688 ◽  
Author(s):  
Iain M. Grace ◽  
Gunnar Olsen ◽  
Juan Hurtado-Gallego ◽  
Laura Rincón-García ◽  
Gabino Rubio-Bollinger ◽  
...  
Keyword(s):  
Seebeck Coefficient ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Electrical Conductance ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Tunneling Microscope ◽  
Single Molecule Junctions

We report measurements on gold|single-molecule|gold junctions, using a modified scanning tunneling microscope-break junction (STM-BJ) technique, of the Seebeck coefficient and electrical conductance of a series of bridged biphenyl molecules.

A scanning tunneling microscope break junction method with continuous bias modulation

Nanoscale ◽  
2015 ◽  
Vol 7 (36) ◽  
pp. 14965-14973 ◽  
Author(s):  
Edward Beall ◽  
Xing Yin ◽  
David H. Waldeck ◽  
Emil Wierzbinski
Keyword(s):  
Scanning Tunneling Microscope ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Tunneling Microscope ◽  
Current Voltage ◽  
Ac Current

A simple STM Break Junction procedure that allows AC current–voltage characterization of molecules with high statistics is presented.

Tunneling Density of States in Quasicrystals and Approximants

1998 ◽  
Vol 12 (05) ◽  
pp. 503-516 ◽  
Author(s):  
D. N. Davydov ◽  
D. Mayou ◽  
C. Berger ◽  
A. G. M. Jansen
Keyword(s):  
Density Of States ◽  
Electron Scattering ◽  
Scanning Tunneling Microscope ◽  
Electron Interaction ◽  
Scanning Tunneling ◽  
Break Junction ◽  
Square Root ◽  
Tunneling Microscope ◽  
Temperature Scanning

Using a low temperature Scanning Tunneling Microscope and a break-junction tunneling technique, the tunneling density of states (DOS) measurements on oxidized and bare surfaces of quasicrystalline icosahedral i-AlPdRe and i-AlCuFe, and of the approximant α-AlMnSi, as well as crystalline non-approximant ω-AlCuFe phase were performed. A narrow pseudogap at the Fermi level of about 50 meV width was found in tunneling spectra of icosahedral and approximant phases. For higher energies, the DOS exhibits a square root energy dependence attributed to electron–electron interaction effects. The tunneling DOS differs from the LMTO calculated DOS. The possible role of the electron scattering and the non-homogeneous electronic structure close to the surface are discussed.

Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

1991 ◽  
Vol 49 ◽  
pp. 378-379
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear
Keyword(s):  
Scanning Tunneling Microscope ◽  
Biological Sample ◽  
Substrate Surface ◽  
Electrochemical Process ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Tunneling Microscope ◽  
E Coli ◽  
Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

STM of freeze-fracture replicas: Problems and promises

1993 ◽  
Vol 51 ◽  
pp. 68-69
Author(s):  
J. T. Woodward ◽  
J. A. N. Zasadzinski
Keyword(s):  
Scanning Tunneling Microscope ◽  
Organic Materials ◽  
Freeze Fracture ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Molecular Scale ◽  
Organic Surfaces ◽  
Metal Layers ◽  
Conductive Surfaces

The Scanning Tunneling Microscope (STM) offers exciting new ways of imaging surfaces of biological or organic materials with resolution to the sub-molecular scale. Rigid, conductive surfaces can readily be imaged with the STM with atomic resolution. Unfortunately, organic surfaces are neither sufficiently conductive or rigid enough to be examined directly with the STM. At present, nonconductive surfaces can be examined in two ways: 1) Using the AFM, which measures the deflection of a weak spring as it is dragged across the surface, or 2) coating or replicating non-conductive surfaces with metal layers so as to make them conductive, then imaging with the STM. However, we have found that the conventional freeze-fracture technique, while extremely useful for imaging bulk organic materials with STM, must be modified considerably for optimal use in the STM.

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