Quantum Thermodynamics of Nanoscale Thermoelectrics and Electronic Devices

Whitney, Robert S.; Sánchez, Rafael; Splettstoesser, Janine

doi:10.1007/978-3-319-99046-0_7

Cited by 20 publications

(35 citation statements)

References 126 publications

(145 reference statements)

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“…The number of research programmes on nano-cooling is rising [22]. In addition, research into the impact of quantum effects on the thermodynamic efficiency of nanostructures [22] has been a long-standing concern.…”

Section: Need For Efficient Modellingmentioning

confidence: 99%

“…The transport methodology satisfies the second law of thermodynamic as the entropy generated by the transfer of electrons from one reservoir to another reservoir is always positive [22]. The non-equilibrium scattering rates are self-consistently dependent on the local electric field (or equivalently the local electrostatic potential), which is not the case for Boltzmann transport.…”

Section: Review Of Modelling Approachesmentioning

confidence: 99%

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Quantum Transport in a Silicon Nanowire FET Transistor: Hot Electrons and Local Power Dissipation

Martı́nez

Barker

2020

Materials

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A review and perspective is presented of the classical, semiclassical and fully quantum routes to the simulation of electrothermal phenomena in ultrascaled silicon nanowire fieldeffect transistors. It is shown that the physics of ultrascaled devices requires at least a coupled electron quantum transport semiclassical heat equation model outlined here. The importance of the local density of states (LDOS) is discussed from classical to fully quantum versions. It is shown that the minimal quantum approach requires selfconsistency with the Poisson equation and that the electronic LDOS must be determined within at least the selfconsistent Born approximation. To bring in this description and to provide the energy resolved local carrier distributions it is necessary to adopt the nonequilibrium Green function (NEGF) formalism, briefly surveyed here. The NEGF approach describes quantum coherent and dissipative transport, Pauli exclusion and nonequilibrium conditions inside the device. There are two extremes of NEGF used in the community. The most fundamental is based on coupled equations for the Green functions electrons and phonons that are computed at the atomically resolved level within the nanowire channel and into the surrounding device structure using a tight binding Hamiltonian. It has the advantage of treating both the nonequilibrium heat flow within the electron and phonon systems even when the phonon energy distributions are not described by a temperature model. The disadvantage is the grand challenge level of computational complexity. The second approach, that we focus on here, is more useful for fast multiple simulations of devices important for TCAD (Technology Computer Aided Design). It retains the fundamental quantum transport model for the electrons but subsumes the description of the energy distribution of the local phonon subsystem statistics into a semiclassical Fourier heat equation that is sourced by the local heat dissipation from the electron system. It is shown that this selfconsistent approach retains the salient features of the fullscale approach. For focus, we outline our electrothermal simulations for a typical narrow Si nanowire gate allaround fieldeffect transistor. The selfconsistent Born approximation is used to describe electronphonon scattering as the source of heat dissipation to the lattice. We calculated the effect of the device selfheating on the current voltage characteristics. Our fast and simpler methodology closely reproduces the results of a more fundamental computeintensive calculations in which the phonon system is treated on the same footing as the electron system. We computed the local power dissipation and “local lattice temperature” profiles. We compared the selfheating using hot electron heating and the Joule heating, i.e., assuming the electron system was in local equilibrium with the potential. Our simulations show that at low bias the source region of the device has a tendency to cool down for the case of the hot electron heating but not for the case of Joule heating. Our methodology opens the possibility of studying thermoelectricity at nanoscales in an accurate and computationally efficient way. At nanoscales, coherence and hot electrons play a major role. It was found that the overall behaviour of the electron system is dominated by the local density of states and the scattering rate. Electrons leaving the simulated drain region were found to be far from equilibrium.

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Section: Need For Efficient Modellingmentioning

confidence: 99%

Section: Review Of Modelling Approachesmentioning

confidence: 99%

Quantum Transport in a Silicon Nanowire FET Transistor: Hot Electrons and Local Power Dissipation

Martı́nez

Barker

2020

Materials

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“…Thermoelectricity, the invention of the 19th century, is still at the forefront of research due to its importance for space exploration and automotive industry [1], and many more branches of modern technology both at large [2] and small [3] scales. Attempts to find high performance thermoelectric bulk materials [4], including those with topologically non-trivial [5] band structure, have seen limited progress.…”

Section: Introductionmentioning

confidence: 99%

Two- and three-terminal far-from-equilibrium thermoelectric nano-devices in the Kondo regime

Eckern

Wysokiński

2020

New J. Phys.

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This paper analyses the thermoelectric power of two-and three-terminal quantum dot devices under large thermal ΔT and voltage V biases, and their performance as thermoelectric heat engines. The focus is on the interaction between electrons, far-from-equilibrium conditions, and strongly nonlinear transport, which all are important factors affecting the usefulness of the devices. To properly characterise the thermoelectric properties under such conditions, two different Seebeck coefficients are introduced, generalizing the linear response expression. In agreement with previous work, we find that the efficiency of the three-terminal thermoelectric heat engine, as measured by the delivered power, is optimal far from equilibrium. Moreover, strong Coulomb interactions between electrons on the quantum dot are found to diminish the efficiency at maximum power, and the maximal value of the delivered power, both in the Kondo regime and beyond.

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“…Indeed, the thermodynamics of those systems has proven to be a key aspect to study. In the last few years, different individual efforts have coalesced to give rise to a new field dubbed “quantum thermodynamics” [ 48 , 49 , 50 , 51 , 52 , 53 , 61 ], which studies the relations among the different energy fluxes that drive the motion of those machines where quantum mechanics plays a fundamental role.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the progress in the theoretical description of quantum motors and pumps, most of the research has focused on parameter conditions that lie close to the thermodynamic equilibrium, i.e., small bias voltages, temperature gradients, or frequencies of the external driving [ 48 , 49 , 50 , 51 , 52 , 53 , 61 ]. This is reasonable since under such conditions, the linear response regime of the nonequilibrium sources gives an accurate description of the problem, greatly simplifying its general treatment.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and Steady State of Quantum Motors and Pumps Far from Equilibrium

Bustos-Marún

Calvo

2019

Entropy

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In this article, we briefly review dynamical and thermodynamical aspects of different forms of quantum motors and quantum pumps. We then extend previous results to provide new theoretical tools for a systematic study of those phenomena at far-from-equilibrium conditions. We mainly focus on two key topics: (1) The steady-state regime of quantum motors and pumps, paying particular attention to the role of higher-order terms in the nonadiabatic expansion of the current-induced forces.(2) The thermodynamical properties of such systems, emphasizing systematic ways of studying the relationship between different energy fluxes (charge and heat currents, and mechanical power) passing through the system when beyond-first-order expansions are required. We derive a general order-by-order scheme based on energy conservation to rationalize how every order of the expansion of one form of energy flux is connected with the others. We use this approach to give a physical interpretation of the leading terms of the expansion. Finally, we illustrate the above-discussed topics in a double quantum dot within the Coulomb-blockade regime and capacitively coupled to a mechanical rotor. We find many exciting features of this system for arbitrary nonequilibrium conditions: A definite parity of the expansion coefficients with respect to the voltage or temperature biases; negative friction coefficients; and the fact that, under fixed parameters, the device can exhibit multiple steady states where it may operate as a quantum motor or as a quantum pump depending on the initial conditions.

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Quantum Thermodynamics of Nanoscale Thermoelectrics and Electronic Devices

Cited by 20 publications

References 126 publications

Quantum Transport in a Silicon Nanowire FET Transistor: Hot Electrons and Local Power Dissipation

Quantum Transport in a Silicon Nanowire FET Transistor: Hot Electrons and Local Power Dissipation

Two- and three-terminal far-from-equilibrium thermoelectric nano-devices in the Kondo regime

Thermodynamics and Steady State of Quantum Motors and Pumps Far from Equilibrium

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