Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower

• Rouzhaji Tuerhong,
• Mauro Boero and
• Jean-Pierre Bucher

Beilstein J. Nanotechnol. 2019, 10, 1243–1250, doi:10.3762/bjnano.10.124

• surfaces [13][14][15][16][17][18][19][20][21]. Low-temperature STM/STS is an ideal tool to study the Kondo effect, which manifests itself by a sharp zero-bias resonance in the conductance spectrum of a localized moment on a conducting substrate, due to the coherent spin-flip scattering between the

• in the gap of the STM is investigated by probing the differential conductance through the junction. The STS spectrum of a MnPc molecule flat-lying on Au(111) is taken with a bare metallic tip and used as a reference spectrum to be compared with the STS result obtained with a MnPc-terminated tip

• spectroscopy (IETS) close to the Fermi level. The differential conductance (dI/dV) spectrum (Figure 2e) reveals a prominent sharp peak close to the zero-bias voltage and two side peaks corresponding to step-like increases in the dI/dV signal (labeled ΔG) at threshold voltages |Vth| = 110 ± 5 meV. This is a

Glucose-derived carbon materials with tailored properties as electrocatalysts for the oxygen reduction reaction

• Rafael Gomes Morais,
• Natalia Rey-Raap,
• José Luís Figueiredo and
• Manuel Fernando Ribeiro Pereira

Beilstein J. Nanotechnol. 2019, 10, 1089–1102, doi:10.3762/bjnano.10.109

• could result in a material with higher electrical conductance, or due to the higher amount of oxygen [13]. The LSV of carbonized samples reveals that although sample CGBM presents a much higher oxygen content, CG and CGBM samples display the same onset potential (0.64 V), which suggests that the more

• positive onset potential of sample AGBM is due to its higher conductance. Moreover, samples AG and AGBM exhibit a second shoulder at more negative potentials, indicating that the ORR mechanism proceeds via the two-electron pathway producing hydrogen peroxide. This second reduction shoulder does not appear

• increases the onset potential regarding the undoped sample (CGBM) from 0.64 V to 0.67 V. Like in activated samples, this is probably due to the smaller particle size obtained after ball milling, which could result in a material with higher electrical conductance. The onset potential of sample N-AGC is

A carrier velocity model for electrical detection of gas molecules

• Ali Hosseingholi Pourasl,
• Sharifah Hafizah Syed Ariffin,
• Mohammad Taghi Ahmadi,
• Razali Ismail and
• Niayesh Gharaei

Beilstein J. Nanotechnol. 2019, 10, 644–653, doi:10.3762/bjnano.10.64

• Fermi level. Therefore, the band gap was calculated to be Eg = 0.193 eV which shows a significant increase after gas adsorption. Furthermore, compared to the band structure of the clean system, the adsorption of NO has changed the band structure so that both the conductance and valence bands are shifted

• to above the Fermi energy level. The valence and conductance band energies were extracted to be EV = 0.493 eV and EC = 0.675 eV, respectively. Therefore, the energy band gap is Eg = 0.182 eV for a doped system. The band structure analysis shows that the Fermi level is located inside the valence band

• conductivity. Furthermore, the energy gap increase results in a conductance decrease of the AGNR as well. These effects on the physical properties and the charge travel between the channel and gas molecules lead to some changes in the electrical characteristics of the AGNR-FET sensor. Figure 6a,b present the I

Transport signatures of an Andreev molecule in a quantum dot–superconductor–quantum dot setup

• Zoltán Scherübl,
• András Pályi and
• Szabolcs Csonka

Beilstein J. Nanotechnol. 2019, 10, 363–378, doi:10.3762/bjnano.10.36

• superconductor tunnel-coupled to the dots, often called a Cooper-pair splitter. We study the three special cases where one of the three non-local mechanisms dominates, and calculate measurable ground-state properties, as well as the zero-bias and finite-bias differential conductance characterizing electron

• associated negative differential conductance in the Cooper-pair splitter, and show that they can arise regardless of the nature of the dominant non-local coupling mechanism. Our results should facilitate the characterization of hybrid devices, and their optimization for various quantum-information-related

• , which allow one to identify and quantify the dominant non-local term. In particular, we describe the ground-state properties (phase diagram, average electron occupation) of the system, the zero-bias conductance describing electron transport through the device in the presence of tunnel-coupled normal

Intuitive human interface to a scanning tunnelling microscope: observation of parity oscillations for a single atomic chain

• Sumit Tewari,
• Jacob Bakermans,
• Christian Wagner,
• Federica Galli and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2019, 10, 337–348, doi:10.3762/bjnano.10.33

• atomic chains are known to show parity oscillations in conductance [8] while going from even to odd number of atoms in the chain. We detect this phenomenon while controllably lifting the chain of atoms and putting it back on the surface. Experimental The experimental setup used here is a custom-built

• conductance of these atomic chains oscillates as a function of the number of atoms in the chain and this effect is known as ‘parity oscillations’. These oscillations were explained [32][33] as an interference effect occurring due to back-scattering of electronic waves at the interface between the bulk and the

• atomic chain. This back-scattering makes this phenomenon similar to that of the Fabry–Pérot interferometer in optics. This was demonstrated in experiments by making length histograms [8] of conductance and it was observed as oscillations in conductance. However, in this method averaging over many atomic

Apparent tunneling barrier height and local work function of atomic arrays

• Neda Noei,
• Alexander Weismann and
• Richard Berndt

Beilstein J. Nanotechnol. 2018, 9, 3048–3052, doi:10.3762/bjnano.9.283

• topographs and from a characteristic signature in differential conductance (dI/dV) spectra. As first reported by Fölsch et al., short single-atom Cu chains on Cu(111) exhibit an unoccupied resonance at 1.5 eV above the Fermi energy EF [36]. Closely related data including the limit of very long chains were

Pattern generation for direct-write three-dimensional nanoscale structures via focused electron beam induced deposition

• Lukas Keller and
• Michael Huth

Beilstein J. Nanotechnol. 2018, 9, 2581–2598, doi:10.3762/bjnano.9.240

• -area substrate. Conceptually, the precursor conductance by diffusive transport along an edge scales linearly with the edge diameter and the inverse of the edge length. The conductance of several edges in parallel sum up, whereas it is the sum of the inverse of the conductances that add if several edges

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

Filling nanopipettes with apertures smaller than 50 nm: dynamic microdistillation

• Evelyne Salançon and
• Bernard Tinland

Beilstein J. Nanotechnol. 2018, 9, 2181–2187, doi:10.3762/bjnano.9.204

• Evelyne Salancon Bernard Tinland Aix Marseille Univ, CNRS, CINAM, Marseille, France 10.3762/bjnano.9.204 Abstract Using nanopipettes with very small apertures (<10 nm) is a good way to improve the spatial resolution in scanning conductance experiments, to monitor single-molecule delivery and to

• small and large angles, would therefore be highly desirable. It would help to improve the spatial resolution in scanning conductance experiments, in optimizing the signal-to-noise ratio during single-molecule delivery and in straining long-molecule stretching during translocation. Small nanopipette

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• reach the ballistic limit [12][13][14]. In spite of these advances, the experimental signatures of MBSs in the nanowire devices deviate significantly in several aspects from the theoretical predictions of minimal models. This is the case, for instance, regarding the behavior of the subgap conductance

• through the proximitized nanowire, which has been addressed in several experiments [10][12][13][14][15][16][17][18][19]. In a long wire (the length of which is much greater than the induced coherence length) the presence of MBSs manifests itself in the appearance of a zero-bias conductance peak the width

• of which is controlled by the normal-state conductance [20]. However, for typical wire lengths explored in actual experiments, which are of the order of a few micrometers, it is expected that the overlap between MBSs located at both ends of the wire gives rise to conventional Andreev bound states

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• integration flexibility. To date, many different gas sensing technologies have been developed. The predominant approaches to utilization are based on changes in the electrical conductance, optical properties, electrochemical potential or resonant frequency of the device [12][13][14][15][16][17][18][19][20][21

Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale

• Arindam Dasgupta,
• Mickaël Buret,
• Nicolas Cazier,
• Marie-Maxime Mennemanteuil,
• Reinaldo Chacon,
• Kamal Hammani,
• Jean-Claude Weeber,
• Juan Arocas,
• Laurent Markey,
• Gérard Colas des Francs,
• Alexander Uskov,
• Igor Smetanin and
• Alexandre Bouhelier

Beilstein J. Nanotechnol. 2018, 9, 1964–1976, doi:10.3762/bjnano.9.187

• different strategies available from the literature ranging from the simple ramping of an applied voltage until breakdown to approaches relying on feedback mechanisms [34]. We finally settled on a method where the applied bias is manually adjusted to control the time evolution of the conductance of the

• current flowing through the device to a voltage output read by the lock-in amplifier. The output of the lock-in is proportional to the amplitude of the modulated current oscillating at F. The conductance of the constriction G is then estimated by dividing the lock-in signal by Vac. The conductance of the

• fairly constant because Joule dissipation is not yet affecting the temperature-dependent resistivity of gold. On increasing Vdc, the temperature of the constriction grows and the conductance starts to fluctuate. The general trend is that G(t) decreases when stepping up Vdc. We also consistently observe a

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• the energy of the single-particle levels. For this reason, if the conductance from the dot to the superconductor is relatively large (high dot–lead transparency) and one can consider the effect of interactions as a small perturbation. Therefore, the ground-state properties, such as the topological

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• ][5][6][7][8][9][10][11][12], and they may also be designed in two-dimensional layouts by means of gate lithography techniques. Over the last few years, several experiments employing such platforms have provided mounting evidence for MBSs, e.g., from zero-bias conductance peaks in N–TS junctions

Solid-state Stern–Gerlach spin splitter for magnetic field sensing, spintronics, and quantum computing

• Kristofer Björnson and
• Annica M. Black-Schaffer

Beilstein J. Nanotechnol. 2018, 9, 1558–1563, doi:10.3762/bjnano.9.147

• spin-up electrons, the only relevant matrix element for the scattering matrix is The conductance is therefore given by It is clear that the very strong dependence of the current on the magnetic flux Br2π makes this setup ideal for measuring magnetic field strength, as a potential alternative to

Spatial Rabi oscillations between Majorana bound states and quantum dots

• Jun-Hui Zheng,
• Dao-Xin Yao and
• Zhi Wang

Beilstein J. Nanotechnol. 2018, 9, 1527–1535, doi:10.3762/bjnano.9.143

• candidate is the hybrid system of a spin–orbit-coupling nanowire and a conventional superconductor. Robust zero-bias conductance peak was first reported in this system, which originates from the self-conjugate nature of Majorana bound states and therefore was wildly recognized as a signature. An exotic

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• topological character of these modes endows them with robustness against perturbations that do not close the superconductor gap, e.g., weak interactions, wire bending, a certain amount of disorder, etc. The most straightforward experimental signature of a Majorana mode is a zero-bias conductance peak that is

Electronic conduction during the formation stages of a single-molecule junction

• Atindra Nath Pal,
• Tal Klein,
• Ayelet Vilan and
• Oren Tal

Beilstein J. Nanotechnol. 2018, 9, 1471–1477, doi:10.3762/bjnano.9.138

• configurations before the realization of a single-molecule bridge based on vanadocene molecules and silver electrodes. With the aid of conductance measurements, inelastic electron spectroscopy and shot noise analysis, we identify the formation of a single-molecule junction in parallel to a single-atom junction

• and examine the interplay between these two conductance pathways. Furthermore, the role of this structure in the formation of single-molecule junctions is studied. Our findings reveal the conductance and structural properties of premature molecular junction configurations and uncover the different

• studies [1][2]. However, information about the conductance properties of such molecular junctions at their early stages of formation is missing. In fact, the conductance signature of premature configurations of molecular junctions (before breaking the atomic scale contact) was studied only for diatomic

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• spin Hall effect [5]. However, no clear signatures of conductance quantization have been observed yet [6][7]. Besides II–VI compound semiconductors, such as HgTe, IV–VI semiconductors support non-trivial edges states as well [8]. In this regard, Dziawa et al. reported evidence of topological

Nanoporous silicon nitride-based membranes of controlled pore size, shape and areal density: Fabrication as well as electrophoretic and molecular filtering characterization

• Axel Seidenstücker,
• Stefan Beirle,
• Fabian Enderle,
• Paul Ziemann,
• Othmar Marti and
• Alfred Plettl

Beilstein J. Nanotechnol. 2018, 9, 1390–1398, doi:10.3762/bjnano.9.131

• (Supporting Information File 1, details in the text and Figure S1). Subsequently, the chambers were filled with a KCl electrolyte and the conductance was determined by applying dc voltages to the Ag/AgCl electrodes and automated current measurements. The results of the according experiments on the membranes A

• , B, and C are shown in Figure 4. Measurements of the fabricated membranes always revealed high ionic conductances. Documented here are the examples A, B, and C in comparison to a membrane without any nanopores (“seal test”). For each of the membranes a conductance was obtained comparable to the

• measured conductance of the setup with removed membrane, created by completely breaking out the freestanding thin silicon nitride layer from its carrier. Thus, the contribution of the nanopores to the total flow resistance in the test setup is found to be very small. To determine the contribution of

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• Green’s functions can be computed numerically from the solution of the Bogoliubov–de Gennes equations of this model (Equation 10). The net spin current turns out to be predominantly sensitive to the Majorana end-modes. Its differential conductance can thus distinguish the polarized Majorana

• sufficiently long wire (εm = 0) the Kondo effect persists only in the spin-channel ↓, whereas for ↑ electrons there appears a dip in the spectral density at ω = 0. The resulting tunneling conductance is then partly reduced (from the perfect value 2e2/h) to the fractional value 3e2/2h [67][68][71][72][73]. In

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• with Majorana bound states (MBSs). The conductance and the noise Fano factor are calculated based on a tight-binding model by adopting a non-equilibrium Green’s function method. It is found that the disorder can effectively lead to a reduction in the conductance peak spacings and significantly suppress

• Majorana zero mode, the noise Fano factor approaches zero in the low bias voltage limit due to the resonant Andreev tunneling. However, the Fano factor is finite in the case of a disorder-induced zero-bias peak. Keywords: conductance peak spacing; disorder; Majorana energy splitting; shot noise; zero-bias

• conductance; Introduction Searching for Majorana bound states (MBSs) have recently received widespread attention due to their potential applications in topologically-protected quantum computing [1][2][3][4][5][6][7][8][9]. In the past two decades, the realizations of MBSs has been predicted in many condensed

Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• , fault-tolerant quantum computation [4][5][6]. Tunneling into such zero-energy MBSs results in a zero-bias peak of high 2e2/h in the tunnelling conductance in normal–superconductor (NS) junctions due to perfect Andreev reflection into a particle–hole symmetric state [7]. Early tunnelling experiments in

The electrical conductivity of CNT/graphene composites: a new method for accelerating transmission function calculations

• Olga E. Glukhova and
• Dmitriy S. Shmygin

Beilstein J. Nanotechnol. 2018, 9, 1254–1262, doi:10.3762/bjnano.9.117

• Olga E. Glukhova Dmitriy S. Shmygin Saratov State University, Saratov, Russian Federation 10.3762/bjnano.9.117 Abstract We present a new universal method to accelerate calculations of transmission function and electrical conductance of 2D materials, the supercell of which may contain hundreds or

• thousands of atoms. The verification of the proposed method is carried out by exemplarily calculating the electrical characteristics of graphene and graphane films. For the first time, we calculated the transmission function and electrical conductance of pillared graphene, composite film of carbon nanotubes

• (CNTs)/graphene. The electrical conductance of different models of this material was calculated in two mutually perpendicular directions. Regularities in resistance values were found. Keywords: carbon composites; electronic properties; interpolation; quantum transport; transmission function

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• from the shell into the wire, Γw, and from the wire into the shell, Γs, can be expressed in terms of the normal-state tunnel resistance in the following manner [20]: where is the contact area, is the wire length, G0 = e2/π is the conductance quantum, νs = ms/2π and νw = (2mw/μw)1/2 are the normal