Quantum dots (QDs) are good model systems for fundamental studies of mesoscopic transport phenomena using thermoelectric effects because of their small size, electrostatically tunable properties and thermoelectric response characteristics that are very sensitive to small thermal biases. Here we provide a review of experimental studies on thermoelectric properties of single QDs realized in two-dimensional electron gases, single-walled carbon nanotubes and semiconductor nanowires. A key requirement for such experiments is to have some methods for nanoscale thermal biasing at one's disposal. We briefly review the main techniques used in the field, namely, heating of the QD contacts, side heating and top heating, and touch upon their relative advantages. The thermoelectric response of a QD as a function of gate potential has a characteristic oscillatory behavior with the same period as is observed for conductance peaks. Much of the existing literature focuses on the agreement between experiments and theory, particularly for amplitude and line-shape of the thermovoltage . A general observation is that the widely used single-electron tunneling approximation for QDs has limited success in reproducing measured . Landauer-type calculations are often found to describe measurement results better, despite the large electron–electron interactions in QDs. More recently, nonlinear thermoelectric effects have moved into the focus of attention, and we offer a brief overview of the experiments done so far. We conclude by discussing open questions and avenues for future work, including the role of asymmetries in tunnel- and capacitive couplings in the thermoelectric behavior of QDs.
Les boîtes quantiques (BQ) sont de bons systèmes pour mener des études fondamentales sur les phénomènes mésoscopiques de transport thermoélectrique, du fait de leurs petites tailles, de leurs propriétés réglables électrostatiquement et de leurs réponses thermoélectriques, qui sont très sensibles à de petits gradients thermiques. Nous passons en revue ici des études expérimentales des propriétés thermoélectriques de BQ individuelles crées dans des gaz d'électrons bidimensionnels, des nanotubes de carbone mono-feuillet et des nanofils semi-conducteurs. Une condition cruciale pour de telles expériences est de disposer de méthodes pour imposer des gradients thermiques aux échelles nanométriques. Nous rappelons brièvement les techniques principales utilisées dans ce but – chauffage Joule des contacts de la boîte, chauffage sur les côtés et par le dessus –, et nous en discutons les avantages respectifs. La réponse thermoélectrique d'une BQ en fonction d'un potentiel de grille présente des oscillations de période identique à celle observée pour les pics de conductance. Une grande part de la litterature insiste sur l'accord entre l'expérience et la théorie, notamment en ce qui concerne l'amplitude et la largeur des pics du thermovoltage . Une observation générale est que l'approximation largement utilisée de l'effet tunnel à un électron décrit avec un succès limité la mesure de . Les calculs à la Landauer s'avèrent souvent mieux décrire les mesures, en dépit des grandes interactions électron–électron à l'œuvre dans ces BQ. Plus récemment, les effets thermoélectriques non linéaires ont attiré l'attention, et nous présentons un bref résumé des expériences menées à bien à ce jour. Nous concluons par une discussion des questions ouvertes et des perspectives pour des travaux futurs, incluant les rôle des asymétries dans les couplages à effet tunnel et capacitifs pour le comportement thermoélectrique des BQ.
Artis Svilans 1; Martin Leijnse 1; Heiner Linke 1
@article{CRPHYS_2016__17_10_1096_0, author = {Artis Svilans and Martin Leijnse and Heiner Linke}, title = {Experiments on the thermoelectric properties of quantum dots}, journal = {Comptes Rendus. Physique}, pages = {1096--1108}, publisher = {Elsevier}, volume = {17}, number = {10}, year = {2016}, doi = {10.1016/j.crhy.2016.08.002}, language = {en}, }
Artis Svilans; Martin Leijnse; Heiner Linke. Experiments on the thermoelectric properties of quantum dots. Comptes Rendus. Physique, Volume 17 (2016) no. 10, pp. 1096-1108. doi : 10.1016/j.crhy.2016.08.002. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2016.08.002/
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