Asymmetric nonlinear conductance of quantum dots with broken inversion symmetry

Linke, Heiner; Sheng, Weifan; Svensson, Anders; Löfgren, Anneli; Christensson, L.; Xu, Hongqi; Omling, P.; Lindelöf, P. E.

doi:10.1103/physrevb.61.15914

Cited by 52 publications

(37 citation statements)

References 34 publications

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“…From an application point of view, the observed nonlinear I-V curves [1][2][3][4][5][6][7][8][9][10][11][12] in these junctions are quite attractive in that the effect persists to room temperature and originates without any special engineering. Initial experimental investigation into the issue sought to add the source of nonlinearity in various ways: The experiment ͑Refs.…”

Section: Introductionmentioning

confidence: 99%

Gap theory of rectification in ballistic three-terminal conductors

Jordan

Büttiker

2008

Phys. Rev. B

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We introduce a model for rectification in three-terminal ballistic conductors, where the central connecting node is modeled as a chaotic cavity. For bias voltages comparable to the Fermi energy, a strong nonlinearity is created by the opening of a gap in the transport window. Both noninteracting cavity electrons at arbitrary temperature as well as the hot-electron regime are considered. Charging effects are treated within the transmission formalism using a self-consistent analysis. The conductance of the third lead in a voltage probe configuration is varied to also model inelastic effects. We find that the basic transport features are insensitive to all of these changes, indicating that the nonlinearity is robust and well suited to applications such as current rectification in ballistic systems. Our findings are in broad agreement with several recent experiments.

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Section: Introductionmentioning

confidence: 99%

Gap theory of rectification in ballistic three-terminal conductors

Jordan

Büttiker

2008

Phys. Rev. B

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“…Recent experiments [24] suggest an asymmetric rectification of the generated heat in a voltage-driven atomic-scale junction. These results are interesting because whereas rectification effects are well understood in the electric case [38][39][40][41][42][43][44] much less is known about the way power is dissipated in a voltage-biased mesoscopic conductor. The linear part of the rectified heat follows from the linear-response Peltier coefficient.…”

mentioning

confidence: 99%

Strongly nonlinear thermovoltage and heat dissipation in interacting quantum dots

Sierra

Sánchez

2014

Phys. Rev. B

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We investigate the nonlinear regime of charge and energy transport through Coulomb-blockaded quantum dots. We discuss crossed effects that arise when electrons move in response to thermal gradients (Seebeck effect) or energy flows in reaction to voltage differences (Peltier effect). We find that the differential thermoelectric conductance shows a characteristic Coulomb butterfly structure due to charging effects. Importantly, we show that experimentally observed thermovoltage zeros are caused by the activation of Coulomb resonances at large thermal shifts. Furthermore, the power dissipation asymmetry between the two attached electrodes can be manipulated with the applied voltage, which has implications for the efficient design of nanoscale coolers. [8,9]. Importantly, nonlinearities and rectification mechanisms that lead to the phenomena reported in Refs. [1,2] can be more easily tested in small conductors with strongly energy-dependent densities of states [3,[10][11][12][13][14][15][16][17][18][19][20][21][22]. We emphasize that there is a close relation between the thermopower of a junction and its heat dissipation properties, as demonstrated in Refs. [23][24][25] for the linear regime of transport. Therefore, ascertaining the conditions under which thermovoltages acquire a significant nonlinear contribution has broader implications for power generation and cooling applications [26].We begin our discussion by noticing that vanishing thermovoltages imply the existence of zero thermocurrent states. Unlike voltage-driven currents, which have a definite sign for a bias voltage V > 0 and never cross the V axis for normal conductors (an exception is the Hall resistance of an illuminated two-dimensional electron gas [27]), electric transport subjected a thermal gradient θ displays regions of positive or negative thermocurrents depending on the thermopower sign (positive for electronlike carriers, negative for holelike ones [28]). Nevertheless, this is not sufficient for the thermocurrent to cross the θ axis since the thermopower is constant in linear response. Therefore, a strongly negative

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“…Therefore, the charge current in the isothermal case, i.e., θ 1 = θ 2 = 0, is always given by I c = (2e 2 /h)tV up to order V 3 . This absence of rectification effects in our two-dimensional topological insulator system is in stark contrast with small conductors coupled to normal reservoirs, in which the V 2 term is generally present [49,[65][66][67][68][69][70][71].…”

Section: Weakly Nonlinear Transportmentioning

confidence: 70%

Nonlinear spin-thermoelectric transport in two-dimensional topological insulators

et al. 2014

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We consider spin-polarized transport in a quantum spin Hall antidot system coupled to normal leads. Due to the helical nature of the conducting edge states, the screening potential at the dot region becomes spin dependent without external magnetic fields nor ferromagnetic contacts. Therefore, the electric current due to voltage or temperature differences becomes spin polarized, its degree of polarization being tuned with the dot level position or the base temperature. This spin-filter effect arises in the nonlinear transport regime only and has a purely interaction origin. Likewise, we find a spin polarization of the heat current, which is asymmetric with respect to the bias direction. Interestingly, our results show that a pure spin current can be generated by thermoelectric means: when a temperature gradient is applied, the created thermovoltage (Seebeck effect) induces a spin-polarized current for vanishingly small charge current. An analogous effect can be observed for the heat transport: a pure spin heat flows in response to a voltage shift even if the thermal current is zero.

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Asymmetric nonlinear conductance of quantum dots with broken inversion symmetry

Cited by 52 publications

References 34 publications

Gap theory of rectification in ballistic three-terminal conductors

Gap theory of rectification in ballistic three-terminal conductors

Strongly nonlinear thermovoltage and heat dissipation in interacting quantum dots

Nonlinear spin-thermoelectric transport in two-dimensional topological insulators

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