Interplay of charge and heat transport in a nano-junction in the out-of-equilibrium cotunneling regime

Chtchelkatchev, N. M.; Glatz, Andreas; Beloborodov, I. S.

doi:10.1088/0953-8984/25/18/185301

Cited by 5 publications

(5 citation statements)

References 22 publications

(63 reference statements)

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“…Surprisingly, for electron transport across a thermal gradient, the transfer of heat continues to occur even when there is no net transfer of charge. This effect could be harnessed, particularly through molecular junctions and wires (1,53,119,120), to control the transfer of thermal energy in reaction networks with complex systems of heat reservoirs. In turn, the use of these reservoirs to control charge current in thermoelectric systems with nonzero Seebeck coefficients could result in the development of devices and electronics that can be harnessed for application in thermally controlled molecular machines.…”

Section: Discussionmentioning

confidence: 99%

Electron transfer across a thermal gradient

Craven

Nitzan

2016

Proc. Natl. Acad. Sci. U.S.A.

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Charge transfer is a fundamental process that underlies a multitude of phenomena in chemistry and biology. Recent advances in observing and manipulating charge and heat transport at the nanoscale, and recently developed techniques for monitoring temperature at high temporal and spatial resolution, imply the need for considering electron transfer across thermal gradients. Here, a theory is developed for the rate of electron transfer and the associated heat transport between donor-acceptor pairs located at sites of different temperatures. To this end, through application of a generalized multidimensional transition state theory, the traditional Arrhenius picture of activation energy as a single point on a free energy surface is replaced with a bithermal property that is derived from statistical weighting over all configurations where the reactant and product states are equienergetic. The flow of energy associated with the electron transfer process is also examined, leading to relations between the rate of heat exchange among the donor and acceptor sites as functions of the temperature difference and the electronic driving bias. In particular, we find that an open electron transfer channel contributes to enhanced heat transport between sites even when they are in electronic equilibrium. The presented results provide a unified theory for charge transport and the associated heat conduction between sites at different temperatures. T he study of electronic transport in molecular nanojunctions naturally involves consideration of inelastic transport, where the transporting electron can exchange energy with underlying nuclear motions (1, 2). Such studies have been motivated by the use of inelastic tunneling spectroscopy, and more recently Raman spectroscopy, as diagnostic tools on one hand, and by considerations of junction stability on the other. In parallel, there has been an increasing interest in vibrational heat transport in nanostructures and their interfaces with bulk substrates (3-11) focusing on structure-transport correlations (12-15), moleculesubstrate coupling (16-18), ballistic and diffusive transport processes (11,19), and rectification (20-22). More recently, noise (23-26), nonlinear response (e.g., negative differential heat conductance), and control by external stimuli (27, 28) have been examined. An important driving factor in this growing interest is the development of experimental capabilities that greatly improve on the ability to gauge temperatures (and "effective" temperatures in nonequilibrium systems) with high spatial and thermal resolutions (29-43) and to infer from such measurement the underlying heat transport processes. In particular, vibrational energy transport/ heat conduction in molecular layers and junctions has recently been characterized using different probes (6,19,(44)(45)(46)(47)(48)(49)(50)(51)(52).The interplay between charge and energy (electronic and nuclear) transport (53-60) is of particular interest as it pertains to the performance of energy-conversion devices, such as therm...

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Section: Discussionmentioning

confidence: 99%

Electron transfer across a thermal gradient

Craven

Nitzan

2016

Proc. Natl. Acad. Sci. U.S.A.

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“…For molecules or small dots, the separation between the levels δ is much larger than the coupling to the leads ν defined below and we can include a single localized level of the dot in the model. This reduces the heating effects always present in small devices [25][26][27], because inelastic cotunneling processes involving excitons in the dot [25,26] are inhibited. In fact, for example comparison between theory and experiment for a spin-1 Kondo effect in a molecule indicates that an equilibrium temperature is well established at very low temperatures [7].…”

Section: Model and Assumptionsmentioning

confidence: 99%

“…We neglect here the effects of phonons which are important in large grains [26] and in molecules [28][29][30][31]. These effects can be incorporated in our NCA formalism [32], and their main manifestations are a narrowing of the peaks due to renormalization of the hybridization and the Kondo temperature, and the appearance of small replicas of the peaks in the conductance discussed here shifted at multiples of the phonon frequencies.…”

Section: Model and Assumptionsmentioning

confidence: 99%

Impact of capacitance and tunneling asymmetries on Coulomb blockade edges and Kondo peaks in nonequilibrium transport through molecular quantum dots

2015

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“…The device shown in Fig. 1 is a standard Single Electron Transistor (SET) [20][21][22][23][24][25][26][27] with one important exception: electrons tunnel through ferroelectric insulating layers. The tunnel junctions between the nanograin and the electrodes form the capacitors with ferroelectric filling (see equivalent electric circuit Fig.…”

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confidence: 99%

Interplay of ferroelectricity and single electron tunneling

et al. 2014

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We investigate the interplay of ferroelectricity and quantum electron transport at the nanoscale in the regime of Coulomb blockade. Ferroelectric polarization in this case is no longer the external parameter but should be self-consistently calculated along with electron hopping probabilities leading to new physical transport phenomena studying in this paper. These phenomena appear mostly due to effective screening of a grain electric field by ferroelectric environment rather than due to polarization dependent tunneling probabilities. At small bias voltages polarization can be switched by a single excess electron in the grain. In this case transport properties of SET exhibit the instability (memory effect).PACS numbers: 72.80.Tm,77.84.Lf Systems with ferroelectric (FE) elements attract much of attention due to their interesting fundamental properties at the nanoscale as well as due to their possible applications in microelectronics, especially in nonvolatile memory devices, in emerging technologies of Terahertz-detecting and in building of advanced (nano)capacitors.1-14 In quantum junctions the ferroelectricity influences electron transport: Tunneling through the FE barriers shows giant electro-resistance effect caused by the strong dependence of electron tunneling probability on the FE polarization and external bias orientations.7,15 Here we focus on the inverse processthe influence of electron transport on ferroelectricity. 2,10The naive guess would be that a single electron, small quantum object, can slightly influence the macroscopic effect -ferroelectricity. However, we show that this is not quite true and discuss the interplay of ferroelectricity and quantum electron transport at the nanoscale in the regime of Coulomb blockade. Polarization in this case is no longer the external parameter but should be self-consistently calculated along with electron hopping probabilities leading to new physical transport phenomena studying in this paper. These phenomena appear mostly due to effective screening of a grain electric field by ferroelectric environment rather than due to polarization dependent tunneling probabilities.Ferroelectrics (FE) are characterized by the polarization P whose direction and magnitude can be changed by applying an external electric field E larger than the ferroelectric switching field, E s . The ground ferroelectric state of a bulk sample is usually not uniformly polarized but divided into domains to lower the electrostatic energy, like in ferromagnets. 16At the nanoscale to influence the polarization of (nano)ferroelectric one can apply strong enough bias to nanotips:2 There is a well developed technique of imaging and control of domain structures in ferroelectric thin films by a tip of a scanning probe microscope, see, e.g., Refs. 2,7,10,[17][18][19] Here we show how ferroelectric polarization switching can be produced by placing a single excess electron at the nanograin. Charged metal particle creates a strong enough electric field, E ≈ 1 MV/cm around it. Numerous ferroelectric (nano)...

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Interplay of charge and heat transport in a nano-junction in the out-of-equilibrium cotunneling regime

Cited by 5 publications

References 22 publications

Electron transfer across a thermal gradient

Electron transfer across a thermal gradient

Impact of capacitance and tunneling asymmetries on Coulomb blockade edges and Kondo peaks in nonequilibrium transport through molecular quantum dots

Interplay of ferroelectricity and single electron tunneling

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