Showing papers by "Yoseph Imry published in 2013"
TL;DR: In this paper, it was shown that for the hopping regime, the thermopowers in both finite two-and three-terminal systems are governed by the edges of the samples, due to the fact that the energy transfer between a transport electron and a conducting terminal is determined by the site most strongly coupled to that terminal.
Abstract: It is shown that for the hopping regime, the thermopowers in both finite two- and three-terminal systems are governed by the edges of the samples. This is due to the fact that the energy transfer between a transport electron and a conducting terminal is determined by the site most strongly coupled to that terminal. One-dimensional systems with both nearest-neighbor and variable-range transport as well as certain types of two-dimensional systems are considered. For a given sample, the changes in the thermopowers due to modifying the bulk are quite limited, compared with those of the conductance. When the small thermopower changes exist, their average over a large ensemble of mesoscopic samples will vanish. We also obtain the distribution of the thermopower in such an ensemble and show that its width approaches a finite limit with increasing sample length. This contrasts with the distribution of conductances in such systems, whose width vanishes in the long sample limit. Finally, we find that the thermal conductances in the three-terminal case have a boundary-dominated contribution, due to nonpercolating conduction paths. This contribution can become dominant when the usual conductance is small enough. All our theoretical statements are backed by numerical computations.
46 citations
TL;DR: In this paper, a three-terminal thermoelectric device based on a p-i-n semiconductor junction is proposed, where the intrinsic region is mounted onto what is typically a bosonic thermal terminal.
Abstract: A three-terminal thermoelectric device based on a p–i–n semiconductor junction is proposed, where the intrinsic region is mounted onto what is typically a bosonic thermal terminal. Remarkably, the figure of merit of the deviceis governed also by the energy distribution of the bosons participating in the transport processes, in addition to the electronic. An enhanced figure of merit can be obtained when the relevant distribution is narrow and the electron–boson coupling is strong (such as for optical phonons). We study the conditions for which the figure of merit of the three-terminal junction can be greater than those of the usual thermoelectrical devices made of the same material. A possible setup with a high figure of merit, based on Bi2Te3/Si superlattices, is proposed.
37 citations
TL;DR: In this article, a three-terminal thermoelectric device based on a $p$-$i$-$n$ semiconductor junction is proposed, where the intrinsic region is mounted onto a, typically bosonic, thermal terminal.
Abstract: A three-terminal thermoelectric device based on a $p$-$i$-$n$ semiconductor junction is proposed, where the intrinsic region is mounted onto a, typically bosonic, thermal terminal. Remarkably, the figure of merit of the device is governed also by the energy distribution of the {\em bosons} participating in the transport processes, in addition to the electronic one. An enhanced figure of merit can be obtained when the relevant distribution is narrow and the electron-boson coupling is strong (such as for optical phonons). We study the conditions for which the figure of merit of the three-terminal junction can be greater than those of the usual thermoelectric devices made of the same material. A possible setup with a high figure of merit, based on Bi$_2$Te$_3$/Si superlattices, is proposed.
32 citations
TL;DR: In this paper, the critical frequency separating the localized and propagating modes in dimensions above two is predicted and the transition relates to the level of disorder in the solid and its dimensionality.
Abstract: When sound waves travel through a disordered solid, vibrational modes above a certain threshold frequency can become localized and stop propagating. Theorists present a minimal model that predicts the critical frequency separating the localized and propagating modes in dimensions above two and explores how the transition relates to the level of disorder in the solid and its dimensionality.
20 citations
TL;DR: The interaction-induced orbital magnetic response of a nanoscale system, modeled by the persistent current in a ring geometry, is evaluated for a system which is a superconductor in the bulk.
Abstract: The interaction-induced orbital magnetic response of a nanoscale system, modeled by the persistent current in a ring geometry, is evaluated for a system which is a superconductor in the bulk. The interplay of the renormalized Coulomb and Frohlich interactions is crucial. The diamagnetic response of the large superconductor may become paramagnetic when the finite-size-determined Thouless energy is larger than or on the order of the Debye energy.
6 citations
TL;DR: In this article, two important features of mesoscopic Aharonov-Bohm (A-B) electronic interferometers are analyzed: decoherence due to coupling with other degrees of freedom and coupled transport of charge and heat.
Abstract: Two important features of mesoscopic Aharonov-Bohm (A-B) electronic interferometers are analyzed: decoherence due to coupling with other degrees of freedom and the coupled transport of charge and heat. We first review the principles of decoherence of electronic interference. We then analyze the thermoelectric transport in a ring threaded by such a flux, with a molecular bridge on one of its arms. The charge carriers may also interact inelastically with the molecular vibrations. This nano-system is connected to three termi- nals; two of them are electric and thermal, held at slightly different chemical potentials and temperatures, and the third is purely thermal. For example, a phonon bath thermalizing the molecular vibrations. When this third terminal is held at a temperature different from those of the electronic reservoirs, both an electrical and a heat current are, in general, gen- erated between the latter. Likewise, a voltage and/or temperature difference between the electronic terminals leads to thermal current between the thermal and electronic terminals. The transport coefficients governing these conversions (due to energy exchange between the electrons and the vibrations) and their dependences on the A-B flux are analyzed. Finally, the decoherence due to these inelastic events is discussed.
4 citations
TL;DR: In this paper, the authors investigate the non-exponential relaxation dynamics of the electron glass out of equilibrium, where a sudden change in carrier density reveals interesting memory effects, and present a novel finite size "domino" effect where the connection to the leads affects the relaxation process of electron glass in mesoscopic systems.
Abstract: We investigate theoretically the slow non-exponential relaxation dynamics of the electron glass out of equilibrium, where a sudden change in carrier density reveals interesting memory effects. The self-consistent model of the dynamics of the occupation numbers in the system successfully recovers the general behavior found in experiments. Our numerical analysis is consistent with both the expected logarithmic relaxation and our understanding of how increasing disorder or interaction slows down the relaxation process, thus yielding a consistent picture of the electron glass. We also present a novel finite size "domino" effect where the connection to the leads affects the relaxation process of the electron glass in mesoscopic systems. This effect speeds up the relaxation process, and even reverses the expected effect of interaction; stronger interaction then leading to a faster relaxation.
1 citations