Diffusion thermopower of a serial double quantum dot

Thierschmann, Holger; Henke, M.; Knorr, Johannes; Maier, Luis; Heyn, Ch.; Hansen, W.; Buhmann, H.; Molenkamp, L. W.

doi:10.1088/1367-2630/15/12/123010

Cited by 43 publications

(47 citation statements)

References 18 publications

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“…The development of an oscillating background for the high T data in Figure 4 f also directly refl ects the experimental data. Our data, while consistent with Thierschmann et al, [ 45 ] demonstrates that V th remains straightforward even in the limit where one QD is much larger than the other and the dot couplings to the leads differ signifi cantly.…”

Section: Characterization Of the Device Formed Using Combined Electrisupporting

confidence: 92%

Using Polymer Electrolyte Gates to Set‐and‐Freeze Threshold Voltage and Local Potential in Nanowire‐based Devices and Thermoelectrics

Svensson

Burke

Carrad

et al. 2014

Adv Funct Materials

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polymer electrolyte gated nanowire transistor consists of a salt-laden polymer gel, e.g., LiClO 4 in poly(ethylene oxide), spanning a gap between a metal gate electrode and the nanowire. A voltage applied to the gate electrode drives migration of Li + and ClO − 4 ions to form electric double layers at the electrode/electrolyte and electrolyte/nanowire interfaces. [ 15 ] This effective transfer of gate charge to within ≈1 nm of the nanowire gives considerably improved gate coupling and sub-threshold characteristics. [ 13,14 ] Whereas earlier work focused on organic semiconductor transistors, [ 15,16 ] and semiconductor nanowire transistors with unpatterned polymer electrolyte fi lms, [ 13 ] this paper presents the fi rst study of the low temperature electrical properties of a nanowire transistor featuring a nanoscale polymer electrolyte patterned by electron beam lithography. [ 14 ] In this paper we focus our attention on the properties and potential uses of a unique aspect of polymer electrolyte gates, namely the fact that the ionic mobility drops rapidly to zero as the temperature T is reduced below approximately 220 K. [ 16 ] This enables the electrolyte's ion distribution to be set and "frozen in" to give a fi xed external charge environment near the nanowire's surface. It holds interesting potential uses in quantum transport studies, which are typically performed at T < 4 K; for example, the ability to freeze in the ion distribution in polymer electrolyte gated nanowires has been recently used to study spin-orbit effects in nanowires. [ 13 ] Here we show that this approach can be extended to add two new features: a) the ability to tune the threshold voltage for conventional electrostatic gates, for example, an insulated, doped substrate [ 6 ] over a wide range; and b) the ability to set the disorder potential for nanowire transistors and quantum devices. The disorder potential breaks the nanowire into a string of quantum dots coupled in series, [ 17 ] with properties that can be tuned using the voltage applied to the polymer electrolyte gate. We characterize our devices using conductance and thermovoltage measurements with a key result being the demonstration that local polymer electrolyte gates are fully compatible with thermoelectric measurements of nanowires [18][19][20][21][22][23][24][25] offering the advantage of strongly reduced thermal conductivity compared to metal gates. This is of high potential interest for solid-state cooling applications, where the ability to control disorder and set an optimal operation point using a gate, may enable optimization of the Using Polymer Electrolyte Gates to Set-and-Freeze Threshold Voltage and Local Potential in Nanowire-based Devices and Thermoelectrics Sofi a Fahlvik Svensson , Adam M. Burke , Damon J. Carrad , Martin Leijnse , Heiner Linke , and Adam P. Micolich * The strongly temperature-dependent ionic mobility in polymer electrolytes is used to "freeze in" specifi c ionic charge environments around a nanowire using a local wrap-gate geometry. This makes...

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Section: Characterization Of the Device Formed Using Combined Electrisupporting

confidence: 92%

Using Polymer Electrolyte Gates to Set‐and‐Freeze Threshold Voltage and Local Potential in Nanowire‐based Devices and Thermoelectrics

Svensson

Burke

Carrad

et al. 2014

Adv Funct Materials

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“…The thermopower of double dots was observed in Ref. [19]. Two-terminal geometries using mesoscopic conductors have been considered, notably using quantum dots [5,20,21,7,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43].…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric energy harvesting with quantum dots

2014

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Abstract. We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn towards quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics.

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“…The device depicted in Fig. b is used as a tunnel‐coupled QD system (). The individual dots are labeled QD1 and QD2.…”

Section: Tunnel‐coupled Quantum Dotsmentioning

confidence: 99%

“…This article discusses recent experiments which explore the thermoelectric properties of QD systems. It is organized as follows: in Section 2, we describe the main experimental techniques that were used to realize the QD devices and to control a temperature bias at the nanoscale.…”

Section: Introductionmentioning

confidence: 99%

“…It is organized as follows: in Section 2, we describe the main experimental techniques that were used to realize the QD devices and to control a temperature bias at the nanoscale. Section 3 presents thermopower experiments on two tunnel‐coupled QDs (). We present the thermopower stability diagram and we discuss the results with the main focus on the region of the triple points, where largest thermovoltage is observed.…”

Section: Introductionmentioning

confidence: 99%

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Thermal control and generation of charge currents in coupled quantum dots

Thierschmann

Arnold

Mittermüller

et al. 2015

Physica Status Solidi (a)

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This article reviews recent thermoelectric experiments on quantum dot (QD) systems. The experiments focus on two types of inter‐dot coupling: tunnel coupling and Coulomb coupling. Tunnel‐coupled QDs allow particles to be exchanged between the attached reservoirs via the QD system. Hence, an applied temperature bias results in a thermovoltage. When being investigated as a function of QD energies, this leads to the thermopower stability diagram. Here, largest thermovoltage is observed in the regions of the triple points. In a QD system which exhibits only capacitive inter‐dot coupling, electron transfer is suppressed. Such a device is studied in a three‐terminal geometry: while one QD connects to the heat reservoir, the other one can exchange electrons with two reservoirs at a lower temperature. When the symmetry of the tunneling coefficients in the cold system is broken, the device becomes an energy harvester: thermal energy is extracted from the heat reservoir and is converted into a directed charge current between the two cold reservoirs. This review illustrates the large potential of multi‐QD devices for thermoelectrics and thermal management at the nanometer‐scale.

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Diffusion thermopower of a serial double quantum dot

Cited by 43 publications

References 18 publications

Using Polymer Electrolyte Gates to Set‐and‐Freeze Threshold Voltage and Local Potential in Nanowire‐based Devices and Thermoelectrics

Using Polymer Electrolyte Gates to Set‐and‐Freeze Threshold Voltage and Local Potential in Nanowire‐based Devices and Thermoelectrics

Thermoelectric energy harvesting with quantum dots

Thermal control and generation of charge currents in coupled quantum dots

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