Controlled Contact to a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="normal">C</mml:mi><mml:mn>60</mml:mn></mml:msub></mml:math>Molecule

Néel, N.; Kröger, J.; Limot, L.; Frederiksen, Thomas; Brandbyge, Mads; Berndt, Richard

doi:10.1103/physrevlett.98.065502

Cited by 143 publications

(166 citation statements)

References 18 publications

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“…2(a) and introduced in Refs. [14,15]. For SnPc-up a contact conductance of %0:052G 0 is obtained in this way.…”

Section: Atomic-scale Control Of Electron Transport Through Single Momentioning

confidence: 99%

“…While the importance of atomic structure and bonding for transport through single-molecule junctions has repeatedly been emphasized, investigations with atomic-scale control of the junction geometry are scarce. Recent scanning tunneling microscope (STM) experiments have provided structural information about the electrodes and the orientation of contacted molecules with atomic precision [12][13][14][15][16]. This opens an avenue for understanding and controlling the current flow through single molecules by combining transport measure ments with the atomic manipulation capabilities of a STM.…”

Section: Atomic-scale Control Of Electron Transport Through Single Momentioning

confidence: 99%

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Atomic-Scale Control of Electron Transport through Single Molecules

et al. 2010

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“…2(a) and introduced in Refs. [14,15]. For SnPc-up a contact conductance of %0:052G 0 is obtained in this way.…”

Section: Atomic-scale Control Of Electron Transport Through Single Momentioning

confidence: 99%

Section: Atomic-scale Control Of Electron Transport Through Single Momentioning

confidence: 99%

Atomic-Scale Control of Electron Transport through Single Molecules

et al. 2010

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“…The fullerene C 60 is a test-bed molecule for molecular electronics and its electrical transport properties have been extensively investigated both experimentally [14][15][16][17][18][19][20][21][22] and theoretically [18,[20][21][22][23][24][25][26][27][28][29][30][31][32]. Also in the context of thermoelectricity, C 60 -based single-molecule junctions have been analyzed and several groups have reported room-temperature thermopower measurements [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Thermal conductance and thermoelectric figure of merit of C60 -based single-molecule junctions: Electrons, phonons, and photons

et al. 2017

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Motivated by recent experiments, we present here an ab initio study of the impact of the phonon transport on the thermal conductance and thermoelectric figure of merit of C60-based single-molecule junctions. To be precise, we combine density functional theory with nonequilibrium Green's function techniques to compute these two quantities in junctions with either a C60 monomer or a C60 dimer connected to gold electrodes, taking into account the contributions of both electrons and phonons. Our results show that for C60 monomer junctions phonon transport plays a minor role in the thermal conductance and, in turn, in the figure of merit, which can reach values on the order of 0.1, depending on the contact geometry. In C60 dimer junctions, phonons are transported less efficiently, but they completely dominate the thermal conductance and reduce the figure of merit as compared to monomer junctions. Thus, claims that by stacking C60 molecules one could achieve high thermoelectric performance, which have been made without considering the phonon contribution, are not justified. Moreover, we analyze the relevance of near-field thermal radiation for the figure of merit of these junctions within the framework of fluctuational electrodynamics. We conclude that photon tunneling can be another detrimental factor for the thermoelectric performance, which has been overlooked so far in the field of molecular electronics. Our study illustrates the crucial roles that phonon transport and photon tunneling can play, when critically assessing the performance of molecular junctions as potential nanoscale thermoelectric devices.

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“…For smaller electrode separations at contact, however, the spin polarization was predicted to drop sharply to zero over a range of ≈ 0.5Å. Relaxations of atomic positions owing to adhesive forces, which have been found for other single-atom [25] and single-molecule [26] contacts, were not included in these calculations. They may shift the range of distances where spin polarization is lost.…”

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Quantized Conductance of a Single Magnetic Atom

Néel

Berndt

2009

Phys. Rev. Lett.

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A single Co atom adsorbed on Cu(111) or on ferromagnetic Co islands is contacted with nonmagnetic W or ferromagnetic Ni tips in a scanning tunneling microscope. When the Co atom bridges two non-magnetic electrodes conductances of 2 e 2 /h are found. With two ferromagnetic electrodes a conductance of e 2 /h is observed which may indicate fully spin-polarized transport.PACS numbers: 68.37. Ef,72.25.Ba,73.23.Ad,73.63.Rt The conductance of nanometer-sized contacts may be decomposed into contributions of transport eigenchannels according to G = G 0 n i=1 τ i , where G 0 = 2e 2 /h is the quantum of conductance (-e: electron charge, h: Planck's constant), and τ i is the transmission probability of the ith channel [1,2]. The factor 2 in the quantum of conductance is due to spin degeneracy. In contacts involving magnetic electrodes the spin degeneracy of transport channels may be lifted. Each spin-polarized channel then may contribute up to G 0 /2 to the total conductance.A quantized conductance of G 0 /2 is expected when a fully spin-polarized current is transmitted with a probability of 1 through a spin-polarized transport channel. These conditions appear difficult to fulfill. Nevertheless, experimental observations of conductance quantization in units of G 0 /2 have repeatedly been reported [3,4,5,6,7,8]. These conductances were observed with [4,6] or without [3,5,7,8] external magnetic fields, for ferromagnetic [3,4,5,6,7] and non-magnetic electrodes [7,8]. On the other hand, the absence of noninteger conductance quantization has also been inferred from experimental results [9,10]. Untiedt et al. showed that contaminants like H 2 or CO modify the conductance and could, in the case of CO adsorption on Pt electrodes, give rise to a conductance of G 0 /2 [10]. A considerable variety of model calculations [11,12,13,14,15] have been performed and support the notion that conductance quantization in units of G 0 /2 is not expected from the investigated ferromagnetic contacts. It should be noted, however, that the modeling performed so far did not include geometrical relaxations of the contacts although the importance of the detailed atomic arrangement has been emphasized [11,15,16,17].The contradictory conclusions reached from the various experiments may be related to a lack of characterisation of the atomic details of the junction. This problem may be reduced by using a cryogenic scanning tunneling microscope to probe the conductance of clean singleatom contacts in ultra-high vacuum. Here we apply this approach to investigate prototypical junctions. A single magnetic atom on a spin-polarized island or a nonmagnetic substrate is contacted with non-magnetic and ferromagnetic tips. We find that the conductance of a single Co atom is G 0 when two non-magnetic electrodes are used. With ferromagnetic electrodes the conductance is G 0 /2. Conductances of ≈ 0.9 G 0 are observed for a combination of a non-magnetic and a ferromagnetic electrode. In contrast to previous experiments, the contact geometry and chemistry are character...

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Controlled Contact to aC60Molecule

Cited by 143 publications

References 18 publications

Atomic-Scale Control of Electron Transport through Single Molecules

Atomic-Scale Control of Electron Transport through Single Molecules

Thermal conductance and thermoelectric figure of merit of C60 -based single-molecule junctions: Electrons, phonons, and photons

Quantized Conductance of a Single Magnetic Atom

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