Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• states in condensed matter devices is attracting strong interest for a few years now [1][2][3][4][5][6][7][8]. The measured zero-bias conductance peaks in hybrid semiconductor/superconductor nanowires have been attributed to the presence of localized Majorana modes on the two ends of the nanowires [9][10

• ][11][12][13][14]. A Majorana mode enhances the zero-bias conductance by allowing a perfect Andreev backscattering at zero excitation energy when the nanowire is attached to a normal lead. These peculiar pairs of states may be seen as nonlocal split fermions, protected by an energy gap that separates

• them from other normal states lying at finite energies. Besides the zero energy of the Majorana state, also the conductance peak height was recently seen to coincide with the expected value 2e2/h [15]. Majorana end states in (quasi) 1D nanowires are inherently localized, i.e., their wave 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

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• velocity vn(E) and density of states ρn(E) of a given mode n at energy E [36]. This product is a constant vn(E)ρn(E) = 1/h, irrespective of the form of εn(k), which leads to the well-known conductance quantum e2/h. For infinitely long, ballistic systems all channels are perfectly transmitted Tn = 1, so one

• can simply count the number of propagating modes to obtain the conductance. If the curvature of the dispersion is negative (here we consider positive energy states) at k = 0, then the mode can contribute twice to the conductance since there are two values of k that fulfill εn(k) = E and have the same

• method [39]. Experiments on normal (not topological) nanowires show a conductance that can be complicated, but reproducible trace for a given nanowire. This means that the measurement can be repeated on the same nanowire and it will give the same conductance trace as long as the sample is kept under

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

• Sahar Pakdel,
• Mahdi Pourfath and
• J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

• potential applications in optoelectronics [34][35][36][37], low thermal conductance with low electrical resistivity for energy generation through thermoelectricity [38], and exotic topological features under strain [39][40][41]. However, it was not until last year that few experimental works brought all

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• detachment of either the methylcyclopentadienyl ring or the methyl group. Detached methylcyclopentadienyl rings and the dissociated methyl groups block the surface active sites and might be the source of organic contamination. Since the composition of the obtained deposits dictate the conductance behavior

Electron interactions with the heteronuclear carbonyl precursor H₂FeRu₃(CO)₁₃ and comparison with HFeCo₃(CO)₁₂: from fundamental gas phase and surface science studies to focused electron beam induced deposition

• Ragesh Kumar T P,
• Paul Weirich,
• Lukas Hrachowina,
• Marc Hanefeld,
• Ragnar Bjornsson,
• Helgi Rafn Hrodmarsson,
• Sven Barth,
• D. Howard Fairbrother,
• Michael Huth and
• Oddur Ingólfsson

Beilstein J. Nanotechnol. 2018, 9, 555–579, doi:10.3762/bjnano.9.53

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• experimentally is related to ferromagnetic atomic chains, which are put on a trivial superconductor [15]. It is believed that MFs can generate a zero-bias conductance peak (ZBP) in the conductance spectrum [16][17][18][19], and indeed the signature of ZBPs has been observed in both systems in tunneling

• not work. In our previous paper [46], we studied the conductance at the junction with a single STM lead. A butterfly-pattern conductance caused by nontrivial Andreev bound states would be observed as we vary the flux, which is distinct from the conductance of a single impurity state localized at the

• junction. Hence, the butterfly pattern can be regarded as a unique property of the nontrivial Andreev bound states. Figure 4a shows the same butterfly-pattern conductance. However, the peak value of the butterfly for each parity-conserved energy spectrum has a 2π period instead of a 4π period. The reason

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• microscope [8][10][11][12][13][14][15]. In situ studies of the dynamics of force interactions, conductance and adhesion in gold point contacts using combined transmission electron microscopy/scanning tunnelling microscopy (TEM-STM) [51][52] and atomic force microscopy/transmission electron microscopy (AFM

Combined scanning probe electronic and thermal characterization of an indium arsenide nanowire

• Tino Wagner,
• Fabian Menges,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2018, 9, 129–136, doi:10.3762/bjnano.9.15

• solid line is extracted from the reconstructed nanowire model U(x, I), whereas the scattered points are calculated from the raw measurements corrected by the static offset, . The nanowire device displays mostly linear I–V characteristics with a slight suppression of the conductance near zero bias

• conductance to the substrate, gs, is the same below electrodes, we obtain = (ge − gs)/Wc = (1.0 ± 0.4) × 107 W·m−2·K−1. This value constitutes only a lower limit, however, since the nanowire is etched below the electrodes. As an upper limit, we consider the interfacial conductivity without heat flow to the

• reduced considerably by cross-sectional measurements of the contact area. As shown above for this nanowire (Figure 3), the electrical contacts were partly limited by tunnelling through a thin native oxide layer. If we consider the electron contribution to the thermal conductance to be negligible [36

The role of ligands in coinage-metal nanoparticles for electronics

• Ioannis Kanelidis and
• Tobias Kraus

Beilstein J. Nanotechnol. 2017, 8, 2625–2639, doi:10.3762/bjnano.8.263

• to a ligand-exchange reaction and one single or a few connections between neighboring metal cores were established during illumination with UV light. The light-induced conductance enhancement of more than one order of magnitude suggested that the diarylethene molecular bridges created a percolating

Inelastic electron tunneling spectroscopy of difurylethene-based photochromic single-molecule junctions

• Youngsang Kim,
• Safa G. Bahoosh,
• Dmytro Sysoiev,
• Thomas Huhn,
• Fabian Pauly and
• Elke Scheer

Beilstein J. Nanotechnol. 2017, 8, 2606–2614, doi:10.3762/bjnano.8.261

• between the open and closed forms of the diarylethene core, when exposed to ultraviolet (UV) or visible light. This transformation results in a significant variation of electrical conductance and vibrational properties of corresponding molecular junctions. We report here a combined experimental and

• conductance. Furthermore, the vibrational eigenmodes of both isomers will be different. To study the vibrational properties of molecular junctions, IET spectroscopy [4][17] was introduced, which is an electronic spectroscopy method applicable at low temperatures. IET measurements are capable of identifying

• inelastic charge transport through single-molecule junctions of a bis(furanylmethanthiol)ethene with a fluorinated cyclopentene bridging unit (C5F-ThM; for nomenclature see [22]). Experimentally measured electrical conductance and IET spectra are compared with first-principles calculations in open and

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

• Sumit Tewari,
• Koen M. Bastiaans,
• Milan P. Allan and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2017, 8, 2389–2395, doi:10.3762/bjnano.8.238

• authors report to have obtained crystalline tips by repeated deep indentation of a Au tip into a Au surface followed by retraction until the contact breaks. These indentation cycles cause plastic deformation of the tip apex [26], which first gives random conductance traces but gradually evolves to

• shape with a direct detection technique rather than studying conductance versus tip displacement or STM image contrast. Experimental The experiments were performed in a Unisoku ultra high vacuum (UHV) and low-temperature STM with a base temperature of 2 K. The in-plane (XY) scan range is set by the

• –surface interaction will be dominated by Au at both sides, while the PtIr base provides better mechanical stability. All the measurements reported here were performed at temperatures between 2 and 4.2 K. Conductance traces Using this STM setup we applied training procedures for the tip apex following the

Adsorbate-driven cooling of carbene-based molecular junctions

• Giuseppe Foti and
• Héctor Vázquez

Beilstein J. Nanotechnol. 2017, 8, 2060–2068, doi:10.3762/bjnano.8.206

• . STM break-junction measurements are often carried out in solution, where, in addition to target molecules, solvent molecules are also present [11][12][13][14][15][16]. The presence of contaminants that might diffuse on the surface and cause fluctuations in conductance or sudden changes in the junction

• only indirect information on the nature of the junction from conductance and forces [14][23][24]. In spite of this, the role of molecular co-adsorbates in elastic and inelastic transport processes has not been studied in detail. Therefore going beyond the approximation of a “clean” junction and

A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

• Colin K. Curtis,
• Antonin Marek,
• Alex I. Smirnov and
• Jacqueline Krim

Beilstein J. Nanotechnol. 2017, 8, 2045–2059, doi:10.3762/bjnano.8.205

• -based data acquisition system was used to record both the crystal resonant frequency and the conductance voltage Vc, from the controller output. The conductance voltage, Vc, is related to the mechanical resistance, Rm, as [34]. Changes in mechanical resistance are directly proportional to changes in

Freestanding graphene/MnO₂ cathodes for Li-ion batteries

• Şeyma Özcan,
• Aslıhan Güler,
• Tugrul Cetinkaya,
• Mehmet O. Guler and
• Hatem Akbulut

Beilstein J. Nanotechnol. 2017, 8, 1932–1938, doi:10.3762/bjnano.8.193

• conductance (resulting in low cyclability) has extremely limited its potential applications [10][13]. Therefore, nanostructured MnO2 has been fabricated and used with carbon materials to achieve excellent conductivity with a large specific surface area [14]. On one hand, reducing the dimensions of the

(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• using voltages between 1.5 and 2 V while higher voltages also switch neighboring molecules. In addition, states 1 and 2 are part of a large and highly ordered self-assembled array and it is possible to read-out the conductance at a specified position, and thus state 1 or 2, in a non-manipulative manner

Transport characteristics of a silicene nanoribbon on Ag(110)

• Ryoichi Hiraoka,
• Chun-Liang Lin,
• Kotaro Nakamura,
• Ryo Nagao,
• Maki Kawai,
• Ryuichi Arafune and
• Noriaki Takagi

Beilstein J. Nanotechnol. 2017, 8, 1699–1704, doi:10.3762/bjnano.8.170

• nanojunction consisting of tip, SiNR and Ag is fabricated. In the differential conductance spectra of the nanojunctions fabricated by this methodology, a peak appears at the Fermi level which is not observed in the spectra measured either for the SiNRs before being lifted up or the clean Ag substrate. We

• SiNR from the substrate electronic system and elucidate the intrinsic properties. We measure the differential conductance (dI/dV) spectra of the nanojunctions and find a sharp peak structure at the Fermi level. Results and Discussion Figure 1a shows a topographic STM image of the Ag(110) surface after

• loop is turned off. Then we approach the tip to the target SiNR while measuring the conductance G at the sample voltage of 100 mV as a function of tip vertical position (Z). We set the position where the tip is fixed initially as Z = 0. Once the tip touches the target, we retract the tip to lift up the

Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions

• Sreetama Banerjee,
• Daniel Bülz,
• Danny Reuter,
• Karla Hiller,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2017, 8, 1502–1507, doi:10.3762/bjnano.8.150

• of the weakly bound e–h pairs into charge carriers available for the electrical transport is influenced by an applied magnetic field, in favour of the latter effect [9][14]. An applied magnetic field will thus trigger an increase in the conductance of the device [9][14]. It should be noted that

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• the pentacene molecules were probed by measuring the differential conductance (dI/dV) in STS experiments. In STS, pentacene reveals two molecular orbitals near the Fermi energy of the substrate, one at negative (−2.1 V) and one at positive bias voltage (+1.2 V) (Figure 2). The absolute peak positions

• . During STM, all bias voltages were applied with respect to the sample, meaning that for negative bias voltages, electrons tunnel from the sample to the tip. For STS measurements, the differential conductance was recorded utilizing a lock-in amplifier. The bias voltage was modulated with an amplitude of

Charge transport in organic nanocrystal diodes based on rolled-up robust nanomembrane contacts

• Vineeth Kumar Bandari,
• Lakshmi Varadharajan,
• Longqian Xu,
• Abdur Rehman Jalil,
• Mirunalini Devarajulu,
• Pablo F. Siles,
• Feng Zhu and
• Oliver G. Schmidt

Beilstein J. Nanotechnol. 2017, 8, 1277–1282, doi:10.3762/bjnano.8.129

• motion in nanocrystals gradually dominates the charge transport. This corresponds to the I–V trace in Figure 2b, which shows a smooth transition from ohmic to SCL. As shown in the upper inset of Figure 2b, the voltage dependence of the conductance (G) demonstrates that with increasing bias the

• conductance increases non-linearly and with decreasing temperature the conductance decreases correspondingly. It is worthy to compare here with the diodes consisting of self-assembly monolayer contacted with rolled-up tube electrodes, which is previously reported by some of the authors of this contribution

Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors

• Dario Zappa,
• Angela Bertuna,
• Elisabetta Comini,
• Navpreet Kaur,
• Nicola Poli,
• Veronica Sberveglieri and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2017, 8, 1205–1217, doi:10.3762/bjnano.8.122

• ions trap free electrons from the surface, thus changing the overall electrical conductance of the material. When we release a reducing gas species in the atmosphere, gas molecules interact with these pre-adsorbed oxygen ions releasing electrons on the surface of the material. This injection of free

• carriers results in an increase (for n-type semiconductors) or decrease (for p-type semiconductors) of the electrical conductance, respectively. For example, if we consider CO as target species to be detected we have (Equation 1) [14]: In the presence of oxidizing species such as NO2, the interaction on

• the oxide surface leads to an increase of the number of adsorbed species from the gas phase. This results in an increase of electrical conductance for for p-type materials and, correspondingly, a decrease for n-type materials. This behaviour can be better explained through the following reactions in

Adsorption characteristics of Er₃N@C₈₀on W(110) and Au(111) studied via scanning tunneling microscopy and spectroscopy

• Sebastian Schimmel,
• Zhixiang Sun,
• Danny Baumann,
• Denis Krylov,
• Nataliya Samoylova,
• Alexey Popov,
• Bernd Büchner and
• Christian Hess

Beilstein J. Nanotechnol. 2017, 8, 1127–1134, doi:10.3762/bjnano.8.114

• center [4]. Dependent on the cluster composition and due to the intercalation inside a protecting carbon cage, intriguing properties emerge. For instance, single molecular magnetism was observed for DySc2N@C80 [5] and conductance switching by tunneling current induced cluster rotations between chiral

• -monolayer (bright half), the slightly visible interfacial reconstruction and the bare Au(111)-surface (dark half) can be seen. Interestingly, as illustrated in Figure 5b and c, spatial variations of the electronic structure occurred. The corresponding differential conductance maps (Figure 5b,c) respectively

Stable Au–C bonds to the substrate for fullerene-based nanostructures

• Taras Chutora,
• Jesús Redondo,
• Bruno de la Torre,
• Martin Švec,
• Pavel Jelínek and
• Héctor Vázquez

Beilstein J. Nanotechnol. 2017, 8, 1073–1079, doi:10.3762/bjnano.8.109

• spread of electronic coupling and conductance values [9][10][11][12]. For an archetypal electrode material in single molecule transport studies such as Au, however, their high mobility at room temperature can lead to a large spread in conductance or to problems in trapping the molecule at the interface

• [19][20]. It might therefore be desirable to achieve strong metal–molecule bonds that result are electronically transparent or exhibit a well-defined conductance. Au–C metal–molecule bonds were found to be highly conducting [21][22]. Here we report on the formation of stable fullerene-based

Study of the correlation between sensing performance and surface morphology of inkjet-printed aqueous graphene-based chemiresistors for NO₂ detection

• F. Villani,
• C. Schiattarella,
• T. Polichetti,
• R. Di Capua,
• F. Loffredo,
• B. Alfano,
• M. L. Miglietta,
• E. Massera,
• L. Verdoliva and
• G. Di Francia

Beilstein J. Nanotechnol. 2017, 8, 1023–1031, doi:10.3762/bjnano.8.103

• . The device performances, in terms of relative conductance variations, upon exposure to NO2 at standard ambient temperature and pressure, are analysed. In addition, we examine the effect of the substrate morphology and, more specifically, of the ink/substrate interaction on the device performances, by

• reported. After an exposure of ten minutes, the devices reach a different percentage increase of the conductance G, defined as: with G0 being the base conductance, measured immediately before the NO2 exposure. It is worth noting that the device fabricated with a lower number of printed layers (D-P17) shows

• substrate surface, so envisaging an indirect effect of the substrate onto the sensing layer morphology. Typical for graphene-based chemiresistors operating at room temperature, the sensing curves show slow recovery behavior. This implies several hours for reaching the initial conductance values or the

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• , setting the flow rate at 500 sccm, the temperature at 25 °C and the relative humidity (RH) at 50%. An increase of the conductance response has been recorded upon exposure towards NO2, whereas a decrease of the signal has been detected towards NH3. The material appears totally insensitive towards CO

• extent. Figure 3 displays the dynamic response of the conductance of the devices towards 1 ppm of NO2. As can be observed, the base conductance values are comparable (GA ≈ GB ≈ 22 µS). During exposure, both chemiresistors exhibit an identical percentage variation of the conductance without reaching a

• plateau. In the figures the asymptotic values of conductance are also displayed. Such quantities have been evaluated by extrapolating the final conductance value by fitting each curve, within the time window of exposure to the analyte, with the exponential function where GMIN/MAX represents the