Enhancement of the effective disorder potential and thermopower in Na<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mi>x</mml:mi></mml:msub></mml:math>CoO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>through electron-phonon coupling

Sangiovanni, Giorgio; Wissgott, P.; Assaad, Fakher F.; Toschi, A.; Held, Karsten

doi:10.1103/physrevb.86.035123

“…If we include spin degeneracy, σ and κ would be double their above values but S would be unchanged. More sophisticated treatments of thermoelectric systems include modelling them with density functional theory methods coupled to a Boltzmann transport theory [172][173][174][175][176]. Broadly speaking these are the Boltzmann theory equivalent of the scattering theory coupled to density functional theory discussed in sect.…”

Section: Comparison With the Boltzmann Equationmentioning

confidence: 99%

“…It can also be extended by replacing Eqs. (174,175) by nonlinear functions of the biases and temperatures. However, whatever one does the model remains phenomenological, and the number of phenomenological parameters increases rather rapidly as one makes the model more sophisticated.…”

Section: Phenomenological Treatment Of Strong Nonlinearitiesmentioning

confidence: 99%

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Benenti,

Casati,

Saito

et al. 2016

Preprint

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In recent years, the study of heat to work conversion has been re-invigorated by nanotechnology. Steady-state devices do this conversion without any macroscopic moving parts, through steady-state flows of microscopic particles such as electrons, photons, phonons, etc. This review aims to introduce some of the theories used to describe these steady-state flows in a variety of mesoscopic or nanoscale systems. These theories are introduced in the context of idealized machines which convert heat into electrical power (heat-engines) or convert electrical power into a heat flow (refrigerators). In this sense, the machines could be categorized as thermoelectrics, although this should be understood to include photovoltaics when the heat source is the sun. As quantum mechanics is important for most such machines, they fall into the field of quantum thermodynamics. In many cases, the machines we consider have few degrees of freedom, however the reservoirs of heat and work that they interact with are assumed to be macroscopic. This review discusses different theories which can take into account different aspects of mesoscopic and nanoscale physics, such as coherent quantum transport, magnetic-field induced effects (including topological ones such as the quantum Hall effect), and single electron charging effects. It discusses the efficiency of thermoelectric conversion, and the thermoelectric figure of merit. More specifically, the theories presented are (i) linear response theory with or without magnetic fields, (ii) Landauer scattering theory in the linear response regime and far from equilibrium, (iii) Green-Kubo formula for strongly interacting systems within the linear response regime, (iv) rate equation analysis for small quantum machines with or without interaction effects, (v) stochastic thermodynamic for fluctuating small systems. In all cases, we place particular emphasis on the fundamental questions about the bounds on ideal machines. Can magnetic-fields change the bounds on power or efficiency? What is the relationship between quantum theories of transport and the laws of thermodynamics? Does quantum mechanics place fundamental bounds on heat to work conversion which are absent in the thermodynamics of classical systems?

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“…However, here the phenomenological functions in Eqs. (174,175) can now be calculated from the microscopic properties of the system. If we take Eq.…”

Section: Weak Nonlinearities For a Simple Model Of A Quantum Dotmentioning

confidence: 99%

“…Then we see that that the the above analysis corresponds to the phenomenological model in section 6.1.1, but now the κs in Eqs. (173)(174)(175) need not be taken as phenomenological constants, they can be extracted from the microscopic theory via…”

Section: Weak Nonlinearities For a Simple Model Of A Quantum Dotmentioning

confidence: 99%

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Benenti

¹

,

Casati

²

,

Saito

³

et al. 2017

View full text Add to dashboard Cite

In recent years, the study of heat to work conversion has been re-invigorated by nanotechnology. Steady-state devices do this conversion without any macroscopic moving parts, through steady-state flows of microscopic particles such as electrons, photons, phonons, etc. This review aims to introduce some of the theories used to describe these steady-state flows in a variety of mesoscopic or nanoscale systems. These theories are introduced in the context of idealized machines which convert heat into electrical power (heat-engines) or convert electrical power into a heat flow (refrigerators). In this sense, the machines could be categorized as thermoelectrics, although this should be understood to include photovoltaics when the heat source is the sun. As quantum mechanics is important for most such machines, they fall into the field of quantum thermodynamics. In many cases, the machines we consider have few degrees of freedom, however the reservoirs of heat and work that they interact with are assumed to be macroscopic. This review discusses different theories which can take into account different aspects of mesoscopic and nanoscale physics, such as coherent quantum transport, magnetic-field induced effects (including topological ones such as the quantum Hall effect), and single electron charging effects. It discusses the efficiency of thermoelectric conversion, and the thermoelectric figure of merit. More specifically, the theories presented are (i) linear response theory with or without magnetic fields, (ii) Landauer scattering theory in the linear response regime and far from equilibrium, (iii) Green-Kubo formula for strongly interacting systems within the linear response regime, (iv) rate equation analysis for small quantum machines with or without interaction effects, (v) stochastic thermodynamic for fluctuating small systems. In all cases, we place particular emphasis on the fundamental questions about the bounds on ideal machines. Can magnetic-fields change the bounds on power or efficiency? What is the relationship between quantum theories of transport and the laws of thermodynamics? Does quantum mechanics place fundamental bounds on heat to work conversion which are absent in the thermodynamics of classical systems?

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“…Several theoretical works addressed the thermoelectricity of Na x CoO 2 [17][18][19][20][21][22][23], ranging from applications of Heikes formula, Boltzmann-equation approaches as well as Kubo-formula-oriented modelings. Correlation effects described beyond conventional density functional theory (DFT) indeed increase the thermopower.…”

mentioning

confidence: 99%

Thermopower Enhancement from Engineering the Na_0.7CoO₂ Interacting Fermiology via Fe Doping

Richter

¹

,

Shopova

²

,

Xie

³

et al. 2018

Advances in Condensed Matter Physics

2

1

0

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The sodium cobaltate system NaxCoO2 is a prominent representant of strongly correlated materials with promising thermoelectric response. In a combined theoretical and experimental study we show that, by doping the Co site of the compound at x=0.7 with iron, a further increase of the Seebeck coefficient is achieved. The Fe defects give rise to effective hole doping in the high-thermopower region of larger sodium content x. Originally filled hole pockets in the angular-resolved spectral function of the material shift to low energy when introducing Fe, leading to a multisheet interacting Fermi surface. Because of the higher sensitivity of correlated materials to doping, introducing adequate substitutional defects is thus a promising route to manipulate their thermopower.

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Enhancement of the effective disorder potential and thermopower in NaxCoO2through electron-phonon coupling

Cited by 7 publications

References 39 publications

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Thermopower Enhancement from Engineering the Na_0.7CoO₂ Interacting Fermiology via Fe Doping

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Enhancement of the effective disorder potential and thermopower in NaxCoO2through electron-phonon coupling

Cited by 7 publications

References 39 publications

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Fundamental aspects of steady-state conversion of heat to work at the nanoscale

Thermopower Enhancement from Engineering the Na0.7CoO2 Interacting Fermiology via Fe Doping

Contact Info

Product

Resources

About

Thermopower Enhancement from Engineering the Na_0.7CoO₂ Interacting Fermiology via Fe Doping