The form of energy termed heat that typically derives from lattice vibrations, i.e., phonons, is usually considered as waste energy and, moreover, deleterious to information processing. However, in this Colloquium, an attempt is made to rebut this common view: By use of tailored models it is demonstrated that phonons can be manipulated similarly to electrons and photons, thus enabling controlled heat transport. Moreover, it is explained that phonons can be put to beneficial use to carry and process information. In the first part ways are presented to control heat transport and to process information for physical systems which are driven by a temperature bias. In particular, a toolkit of familiar electronic analogs for use of phononics is put forward, i.e., phononic devices are described which act as thermal diodes, thermal transistors, thermal logic gates, and thermal memories. These concepts are then put to work to transport, control, and rectify heat in physically realistic nanosystems by devising practical designs of hybrid nanostructures that permit the operation of functional phononic devices; the first experimental realizations are also reported. Next, richer possibilities to manipulate heat flow by use of time-varying thermal bath temperatures or various other external fields are discussed. These give rise to many intriguing phononic nonequilibrium phenomena such as, for example, the directed shuttling of heat, geometrical phase-induced heat pumping, or the phonon Hall effect, which may all find their way into operation with electronic analogs.

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Colloquium : Phononics: Manipulating heat flow with electronic analogs and beyond

Understanding energy dissipation and transport in nanoscale structures is of great importance for the design of energy-efficient circuits and energy-conversion systems. This is also a rich domain for fundamental discoveries at the intersection of electron, lattice (phonon), and optical (photon) interactions. This review presents recent progress in understanding and manipulation of energy dissipation and transport in nanoscale solid-state structures. First, the landscape of power usage from nanoscale transistors (∼10−8 W) to massive data centers (∼109 W) is surveyed. Then, focus is given to energy dissipation in nanoscale circuits, silicon transistors, carbon nanostructures, and semiconductor nanowires. Concepts of steady-state and transient thermal transport are also reviewed in the context of nanoscale devices with sub-nanosecond switching times. Finally, recent directions regarding energy transport are reviewed, including electrical and thermal conductivity of nanostructures, thermal rectification, and the role of ubiquitous material interfaces. 
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/pdf/energy-dissipation-and-transport-in-nanoscale-devices-2fj1ezlyhz.pdf

Energy dissipation and transport in nanoscale devices

Understanding energy dissipation and transport in nanoscale structures is of great importance for the design of energy-efficient circuits and energy-conversion systems. This is also a rich domain for fundamental discoveries at the intersection of electron, lattice (phonon), and optical (photon) interactions. This review presents recent progress in understanding and manipulation of energy dissipation and transport in nanoscale solid-state structures. First, the landscape of power usage from nanoscale transistors (~10^-8 W) to massive data centers (~10^9 W) is surveyed. Then, focus is given to energy dissipation in nanoscale circuits, silicon transistors, carbon nanostructures, and semiconductor nanowires. Concepts of steady-state and transient thermal transport are also reviewed in the context of nanoscale devices with sub-nanosecond switching times. Finally, recent directions regarding energy transport are reviewed, including electrical and thermal conductivity of nanostructures, thermal rectification, and the role of ubiquitous material interfaces.

/pdf/energy-dissipation-and-transport-in-nanoscale-devices-17sw2ubrhz.pdf

Energy Dissipation and Transport in Nanoscale Devices

Advances in the fabrication and characterization of nanoscale systems now allow for a better understanding of one of the most basic issues in science and technology: the flow of heat at the microscopic level. In this Colloquium recent advances are surveyed and an understanding of physical mechanisms of energy transport in nanostructures is presented, focusing mainly on molecular junctions and atomic wires. Basic issues are examined such as thermal conductivity, thermoelectricity, local temperature and heating, and the relation between heat current density and temperature gradient---known as Fourier's law. Both theoretical and experimental progress are critically reported in each of these issues and future research opportunities in the field are discussed.

Colloquium: Heat flow and thermoelectricity in atomic and molecular junctions

https://www3.nd.edu/~sst/teaching/AME60634/homework/2011_IJTS_Walker_Roberts_thermal_rectification_review.pdf

A review of thermal rectification observations and models in solid materials

We report the observation of thermal rectification in a semiconductor quantum dot, as inferred from the asymmetric line shape of the thermopower oscillations. The asymmetry is observed at high in-plane magnetic fields and caused by the presence of a high orbital momentum state in the dot.

https://iopscience.iop.org/article/10.1088/1367-2630/10/8/083016/pdf

Quantum dot as thermal rectifier

The thermopower of a Kondo-correlated gate-defined quantum dot is studied using a current heating technique. In the presence of spin correlations, the thermopower shows a clear deviation from the semiclassical Mott relation between thermopower and conductivity. The strong thermopower signal indicates a significant asymmetry in the spectral density of states of the Kondo resonance with respect to the Fermi energies of the reservoirs. The observed behavior can be explained within the framework of an Anderson-impurity model.

/pdf/thermopower-of-a-kondo-spin-correlated-quantum-dot-zp8utttqdv.pdf

Thermopower of a Kondo spin-correlated quantum dot.

We have studied the temperature-dependent thermopower of gate-defined, lateral quantum dots in the Coulomb blockade regime using an electron heating technique. The line shape of the thermopower oscillations depends strongly on the contributing tunneling processes. Between $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and $40\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$ a crossover from a pure sawtooth to an intermittent sawtoothlike line shape is observed. The latter is attributed to the increasing dominance of cotunneling processes in the Coulomb blockade regime at low temperatures.

https://arxiv.org/pdf/cond-mat/0608193.pdf

R. Scheibner

Papers

Quantum dot as thermal rectifier

Thermopower of a Kondo spin-correlated quantum dot.

Quantum dot as thermal rectifier

Sequential and cotunneling behavior in the temperature-dependent thermopower of few-electron quantum dots