Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• their electron or hole character within the shell is a linear thermoelectric coefficient of the thermopower defined as [74] where the Kondo temperature TK is given by the center and the width of the Kondo resonance, with where ls labels the dot states active in the Kondo processes [64]. Plots of are

• associated with the given resonances. At this point it should be mentioned that one should look at the high-temperature results in Figure 6b with some caution, in particular, at those that concern the thermopower. Inelastic processes, for example, these resulting from electron–phonon interaction are

• and ribbons is tens of micrometers even at room temperature. It has been also shown that the phonon contribution to the thermopower of quantum dots is greatly suppressed [81]. The Landauer-type formulas we use strictly apply only to elastic transport. The electron part of the thermopower is very

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• interacting QD connected to electrodes of massless Dirac fermions in the zero-bias voltage limit [36][37]. The zero-bias conductance plots reveal an impurity quantum phase transition between the Kondo and local moment regimes. Furthermore, the thermopower changes its sign when the temperature approaches the

• Kondo temperature. In a recent study, the thermoelectric properties of a noninteracting QD coupled to massless Dirac fermions have been analyzed using the EOM technique [38]. At low temperature, by tuning the voltage of the metallic gate electrode, this QD system reaches large values of thermopower and

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• efficiency of the material could be expressed in terms of figure-of-merit, ZT, defined as dimensionless quantity ZT = S2·σ·T/κ , where S is the thermopower (Seebeck coefficient), σ is the electrical conductivity, T is the absolute temperature and κ is the thermal conductivity. There were many concepts for

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

• thermopower measured across the single-molecule junction. Keywords: inelastic electron tunneling; molecular quantum dot; Kondo physics; single molecule; thermopower; tunnel junction; Introduction Scanning tunneling microscopy (STM) has the capability to detect the electron transport through a molecule not

• suspended in a tunneling junction of an STM has not been studied yet. Here we describe an approach that allows for achieving, in a controlled manner, such a configuration and to analyze in detail how the Kondo correlation affects the IETS and yieds the non-linear thermopower accross the leads. Results and

• tunneling through excitation of molecular vibration modes. Parameter-dependent transport in a molecular junction In order to gain additional information about the kinetics of carriers not contained in the current–voltage characteristics we want to evaluate the impact of the zero-bias peak on the thermopower

Enhancement in thermoelectric properties due to Ag nanoparticles incorporated in Bi₂Te₃ matrix

• Srashti Gupta,
• Dinesh Chandra Agarwal,
• Bathula Sivaiah,
• Sankarakumar Amrithpandian,
• Kandasami Asokan,
• Ajay Dhar,
• Binaya Kumar Panigrahi,
• Devesh Kumar Avasthi and
• Vinay Gupta

Beilstein J. Nanotechnol. 2019, 10, 634–643, doi:10.3762/bjnano.10.63

• incorporated in Bi2Te3 annealed at 773 K shows mainly hexagonally shaped structures with particle sizes of 2–20 nm and 40–80 nm (for 5 wt % Ag) and 10–60 nm (for 20 wt % Ag). Interestingly, the samples annealed at 573 K show the highest Seebeck coefficient (S, also called thermopower) at room temperature (p

• -type behavior) for 5% Ag which is increased ca. five-fold in comparison to Ag-free Bi2Te3, whereas for samples with the same content (5% Ag) annealed at 773 K the increment in thermopower is only about three-fold with a 6.9-fold enhancement of the power factor (S2σ). The effect of size and shape of the

• nanoparticles on thermoelectric properties can be understood on the basis of a carrier-filtering effect that results in an increase in thermopower along with a control over the reduction in electrical conductivity to maintain a high power factor yielding a high figure of merit. Keywords: bismuth telluride

Magnetism and magnetoresistance of single Ni–Cu alloy nanowires

• Andreea Costas,
• Camelia Florica,
• Elena Matei,
• Maria Eugenia Toimil-Molares,
• Ionel Stavarache,
• Andrei Kuncser,
• Victor Kuncser and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2018, 9, 2345–2355, doi:10.3762/bjnano.9.219

• -resistance and magneto-thermopower measurements on single Co–Ni alloy nanowires have been reported [10]. Several methods have been reported for the controlled fabrication of magnetic nanowires including lithographical techniques, chemical vapor deposition and hydrothermal growth [11][12][13]. The main

Thermo-voltage measurements of atomic contacts at low temperature

• Ayelet Ofarim,
• Bastian Kopp,
• Thomas Möller,
• León Martin,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 767–775, doi:10.3762/bjnano.7.68

• Ayelet Ofarim Bastian Kopp Thomas Moller Leon Martin Johannes Boneberg Paul Leiderer Elke Scheer Department of Physics, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany 10.3762/bjnano.7.68 Abstract We report the development of a novel method to determine the thermopower of

• measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature. Keywords: atomic contacts; finite element simulations; laser heating; low temperature; mechanically

• controllable break-junction; temperature determination; thermopower; Introduction The energy and heat management in electronic devices has become a challenge in recent years due to the down-scaling of electronic components to the nanoscale, where the transport is governed by quantum-mechanical properties

Charge and heat transport in soft nanosystems in the presence of time-dependent perturbations

• Alberto Nocera,
• Carmine Antonio Perroni,
• Vincenzo Marigliano Ramaglia and
• Vittorio Cataudella

Beilstein J. Nanotechnol. 2016, 7, 439–464, doi:10.3762/bjnano.7.39

• charge but also on heat transport [21][22][23][24]. In particular, thermopower and thermal conductances have been measured and theoretically calculated in molecular junctions [25][26][27][28][29]. The role of vibrational degrees of freedom and their coupling with electrons have a fundamental importance

Invariance of molecular charge transport upon changes of extended molecule size and several related issues

• Ioan Bâldea

Beilstein J. Nanotechnol. 2016, 7, 418–431, doi:10.3762/bjnano.7.37

• thermopower) at zero temperature. Furthermore, examples are presented that demonstrate that treating parts of electrodes adjacent to the embedded molecule and the remaining semi-infinite electrodes at different levels of theory (which is exactly what most NEGF-DFT approaches do) is a procedure that yields

• zero temperature. Low-temperature properties like the low bias conductance (and therefore also the related β factor of exponential attenuation with increasing molecular size) as well as other properties (e.g., thermopower [45]), to which only energies very close to the equilibrium Fermi level

Thermoelectricity in molecular junctions with harmonic and anharmonic modes

• Bijay Kumar Agarwalla,
• Jian-Hua Jiang and
• Dvira Segal

Beilstein J. Nanotechnol. 2015, 6, 2129–2139, doi:10.3762/bjnano.6.218

• thermopower, a linear response quantity, also referred to as the Seebeck coefficient, is utilized as an independent tool for probing the energetics of molecular junctions [17][18][19][20][21][22][23][24]. Experimental efforts identified orbital hybridization, contact-molecule energy coupling and geometry, and

• current by and the heat current by . The resulting expansions are cumbersome thus we write them formally in terms of the coefficients ai,j, (i,j = h,p), For and with Π being the Peltier coefficient [46][47], we identify the electrical conductance the thermopower the electron contribution to the

• case, but at low temperatures, ω0/T > > 1, when the excitation rate is negligible relative to the relaxation rate, the two models provide the same results. (ii) Since the expressions for the currents in the HO and the AH models are proportional to each other, the resulting thermopower and figure of

Electron and heat transport in porphyrin-based single-molecule transistors with electro-burnt graphene electrodes

• Hatef Sadeghi,
• Sara Sangtarash and
• Colin J. Lambert

Beilstein J. Nanotechnol. 2015, 6, 1413–1420, doi:10.3762/bjnano.6.146

• orbitals relative to the EBG Fermi energy, we predict HOMO-dominated transport. An on–off ratio as high as 150 is predicted for the device, which could be utilized with small gate voltages in the range of ±0.1 V. A positive thermopower of +280 μV/K is predicted for the device at the theoretical Fermi

• energy. The sign of the thermopower could be changed by tuning the Fermi energy. By gating the junction and changing the Fermi energy by +10 meV, this can be further enhanced to +475 μV/K. Although the electrodes and molecule are symmetric, the junction itself can be asymmetric due to different binding

• order Vds. Figure 7 shows the thermopower, S, and the electronic contribution to the thermal conductance, κ, of the PM–EBG device. The device generated a maximum thermopower of 280 μV/K at 110 K, which then decreased at higher temperatures, as shown in Figure 7a. Furthermore, the thermal conductance of

Alternative types of molecule-decorated atomic chains in Au–CO–Au single-molecule junctions

• Zoltán Balogh,
• Péter Makk and
• András Halbritter

Beilstein J. Nanotechnol. 2015, 6, 1369–1376, doi:10.3762/bjnano.6.141

• obtained by further techniques such as noise [3][4], thermopower [5][6] or inelastic spectroscopy [11][12][13][14] measurements. However, it has been recently realized that just by the advanced statistical analysis of the measured conductance traces essential information can be obtained. To this end

Can molecular projected density of states (PDOS) be systematically used in electronic conductance analysis?

• Tonatiuh Rangel,
• Gian-Marco Rignanese and
• Valerio Olevano

Beilstein J. Nanotechnol. 2015, 6, 1247–1259, doi:10.3762/bjnano.6.128

• experimental community. Indeed, the theoretical analysis of quantum transport is often used for interpretation of the measurements by predicting trends (for example, for the sign of the thermopower), for obtaining independent arguments, or for checking the validity of the experimental work. This paper is

Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

• Hatef Sadeghi,
• Sara Sangtarash and
• Colin J. Lambert

Beilstein J. Nanotechnol. 2015, 6, 1176–1182, doi:10.3762/bjnano.6.119

• values as high as ZTe = 2.45 are obtained. All thermoelectric properties can be further enhanced by tuning the Fermi energy of the leads. Keywords: graphene nanoribbons; quantum transport; thermal conductance; thermoelectric figure of merit; thermopower; Introduction Nowadays, the performance of

• electronic contribution to the thermal conductance κ(T), the thermopower (Seebeck coefficient) S(T) and the Peltier coefficient Π(T) of a junction as a function of the temperature T can be obtained by calculating the transmission probability T(E) of the electrons with energy E passing from one electrode to

• suppressed due to the presence of the pore, whereas the high-transmission feature in the vicinity of the Fermi energy still preserved. This improves the thermopower (Figure 2e) by a factor of 4 and reduces the electronic thermal conductance significantly (Figure 2d), leading to a significant enhancement of

Review of nanostructured devices for thermoelectric applications

• Giovanni Pennelli

Beilstein J. Nanotechnol. 2014, 5, 1268–1284, doi:10.3762/bjnano.5.141

• a circuit made of different materials and subjected to a temperature gradient. The Seebeck coefficient S, also indicated as thermopower, can be written as: A precise expression for S takes into account the temperature gradient ∂T/∂x and the generated electric field ε = −∂V/∂x at the electrical

Transport through molecular junctions

• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2011, 2, 691–692, doi:10.3762/bjnano.2.74

• problem and help build confidence in our interpretations. Apart from direct conductance measurements, one now measures properties such as thermopower, shot noise, Raman scattering, photo-induced switching, and gate-induced level shifts, all at the single-molecule level. Moreover, by systematic variation