Impact of electron–phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime

• Patryk Florków and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2021, 12, 1209–1225, doi:10.3762/bjnano.12.89

• strength of electron–phonon interaction, the system is occupied by a different number of electrons that effectively interact with each other repulsively or attractively. This leads, together with the interference effects, to different spin or charge Fano–Kondo effects. Keywords: Fano effect; Kondo effect

• ; polarons; quantum dots; Introduction As the dimension of a mesoscopic system decreases, interactions between electrons become more important and many-body resonances build up. As a consequence, new transport paths are opened. The key phenomenon of strong correlations is the Kondo effect, which arises from

• degeneracy, for example, in the case of fourfold spin–orbital degeneracy not only spin, but also orbital pseudo-spin can be screened. Such SU(4) Kondo effect resonances have been observed in vertical QDs [10], in capacitively coupled dots [13], and in carbon nanotubes [14][15][16][17]. There is currently

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

• different types. Full spin–orbital degeneracy might be recovered at zero field and, correspondingly, the SU(4) Kondo effect sets in. We point out the possibility of the occurrence of electron–hole Kondo effects in slanting magnetic fields, which we predict to occur in magnetic fields with an orientation

• close to perpendicular. When the field approaches a transverse orientation a crossover from SU(2) or SU(3) symmetry into SU(4) is observed. Keywords: carbon nanotubes; Kondo effect; mesoscopic transport; quantum dots; valleytronics; Introduction Due to their remarkable electronic, transport

• introduces parallel or antiparallel alignments of spin and angular momentum. The energy of SO coupling is comparable to the energy scale of the Kondo effect. Therefore, taking this perturbation into account is important when analyzing many-body effects in these systems. Several interesting papers have been

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

• 10.3762/bjnano.11.17 Abstract Background: Quantum dots connected to larger systems containing a continuum of states like charge reservoirs allow the theoretical study of many-body effects such as the Coulomb blockade and the Kondo effect. Results: Here, we analyze the nonequilibrium Kondo effect and

• graphene-based quantum dot system provides a platform for potential applications of nanoelectronics. Furthermore, we also propose an experimental setup for performing measurements in order to verify our model. Keywords: graphene; Kondo effect; magnetic field; pseudogap Anderson model; quantum dot

• ][39][40]. The choice of electrodes can have a significant effect on the transport properties of the QD system. In the present work, we study the nonequilibrium Kondo effect and the transport properties in a QD coupled to graphene-based leads by solving the pseudogap Anderson model [36][37][38][39][40

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

• gaps where the tunneling barrier asymmetry at the STM–molecule junction becomes less critical. This asymmetry in the spectrum may suggest that two different vibration-assisted electron-transfer processes apparently compete, one involving a vibration-mediated Kondo effect, and the other, an inelastic

The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface

• Luiza Buimaga-Iarinca and
• Cristian Morari

Beilstein J. Nanotechnol. 2019, 10, 706–717, doi:10.3762/bjnano.10.70

• valence bonding or quenching of magnetic moments [73][74][75][76][77]. Since the quantitative estimation of the Kondo effect is beyond the limits of mean-field theories (such as DFT) we can provide a qualitative discussion based on experimental results for the Kondo effect in similar systems. It was shown

• that Kondo effect of organo-metallic compounds adsorbed on coinage metals is sensitive to the manipulation of the chemical bonds [73][74]. The Kondo effect in Co-porphyrins on Au(111) can be switched on or off by binding a NO group to the molecule [73]. Also, the changes in molecular conformation can

• that at the Co-phtalocyanine/Au interface, the magnetic moment of the Co atom is completely quenched by the molecule–substrate interaction [76]. As commented in the paragraph on the Kondo effect, the presence of additional linkers may lead to a perturbations in the crystal field that ultimately could

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

• studies came from the fact that the QD can be driven into the magnetic regime where it represents a spin-1/2 impurity subject to Kondo screening by the leads. The Kondo effect then competes against the superconducting bulk gap and one encounters local quantum phase transitions. By now, good agreement

• between experiment and theory has been established. Rather than studying the fate of the Kondo effect in the S–QD–TS setting of Figure 1a, we here pursue two more modest goals. First, we shall discuss the cotunneling regime in detail, where one can employ perturbation theory in the dot–lead couplings

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

• the Majorana quasiparticles, focusing on their magnetic polarization that has been recently reported by S. Jeon et al. (Science 2017, 358, 772). Finally, we study leakage of these polarized Majorana quasiparticles into side-attached nanoscopic regions and confront them with the subgap Kondo effect

• near to the singlet–doublet phase transition. Keywords: bound states in superconductors; Majorana quasiparticles; subgap Kondo effect; Introduction Magnetism is usually detrimental to superconductivity because it breaks the Cooper pairs (at the critical field strength Hc2). There are, however, a few

• between the opposite spin electrons can bring additional important effects. In the proximitized quantum dots it can lead to a parity change (quantum phase transition) with further influence on the subgap Kondo effect (driven by effective spin-exchange coupling with mobile electrons). Furthermore, such

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

• ][24][25][26][27][28]. However, it is suggested that such zero-bias features could also be induced by non-topological physics such as Kondo effect [31], smooth confinement [32], or strong disorder [33][34][35]. In one-dimensional case, the hybridization of the pair of MBSs localized at the wire ends

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• electronic interactions and correlations, which can be very strong in the confined molecular orbitals. Approaches beyond mean-field-type approximations are required for the treatment of correlation effects such as Coulomb blockade and the Kondo effect [14]. Such interactions not only occur within a single

Vibration-mediated Kondo transport in molecular junctions: conductance evolution during mechanical stretching

• David Rakhmilevitch and
• Oren Tal

Beilstein J. Nanotechnol. 2015, 6, 2417–2422, doi:10.3762/bjnano.6.249

• David Rakhmilevitch Oren Tal Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 10.3762/bjnano.6.249 Abstract The vibration-mediated Kondo effect attracted considerable theoretical interest during the last decade. However, due to lack of extensive experimental

• demonstrations, the fine details of the phenomenon were not addressed. Here, we analyze the evolution of vibration-mediated Kondo effect in molecular junctions during mechanical stretching. The described analysis reveals the different contributions of Kondo and inelastic transport. Keywords: correlated systems

• ; electron–phonon interactions; Kondo effect; molecular junctions; vibrations; Introduction Molecular junctions are an attractive test-bed for electronic effects such as Kondo physics [1][2][3][4][5] and electron–vibration interaction [6][7][8][9][10]. These junctions are composed of individual molecules

Interaction of spin and vibrations in transport through single-molecule magnets

• Falk May,
• Maarten R. Wegewijs and
• Walter Hofstetter

Beilstein J. Nanotechnol. 2011, 2, 693–698, doi:10.3762/bjnano.2.75

• molecule. Based on numerical renormalization group calculations we show that, despite the longitudinal anisotropy barrier and small transverse anisotropy, vibrational fluctuations can induce quantum spin-tunneling (QST) and a QST-Kondo effect. The interplay of spin scattering, QST and molecular vibrations

• can strongly enhance the Kondo effect and induce an anomalous magnetic field dependence of vibrational Kondo side-bands. Keywords: molecular electronic devices; molecular magnets; nanoelectronic devices; quantum dots; Introduction Transport measurements on nanometer-sized magnetic systems address

• have not been studied. One candidate that may enable the sensitive probing of such a coupling of the SMM spin to vibrations is a specific type of Kondo effect induced by quantum spin-tunneling (QST). This QST, through the energy barrier arising from a dominant uni-axial magnetic anisotropy term, relies