Quantum oscillations in confined and degenerate Fermi gases. I. Half-vicinity model

Aydin, Alhun; Şişman, Altuğ

doi:10.1016/j.physleta.2018.02.006

Cited by 11 publications

(8 citation statements)

References 42 publications

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“…For even larger chemical potentials, µ 2 > 0.7 eV, the thermodefect voltage drops substantially for all the three types of longitudinal vacancies and show damped oscillations around zero i.e., both positive and negative voltages are possible for high chemical potentials. These oscillations are associated with the degeneracy effects originated from the Fermi gas properties [11,71,72]. We note here that very high values of the chemical potential, such as > 1 eV, are difficult to utilize in practice [73] and values larger than 2.5 eV even falls outside the validity of the tight-binding model [58].…”

Section: A Vacanciesmentioning

confidence: 93%

Thermodefect voltage in graphene nanoribbon junctions

Aydin,

Sisman,

Fransson

et al. 2021

Preprint

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Thermoelectric junctions are often made of components of different materials characterized by distinct transport properties. Single material junctions, with the same type of charge carriers, have also been considered to investigate various classical and quantum effects on the thermoelectric properties of nanostructured materials. We here introduce the concept of defect-induced thermoelectric voltage, namely, thermodefect voltage, in graphene nanoribbon (GNR) junctions under a temperature gradient. Our thermodefect junction is formed by two GNRs with identical properties except the existence of defects in one of the nanoribbons. At room temperature the thermodefect voltage is highly sensitive to the types of defects, their locations, as well as the width and edge configurations of the GNRs. We demonstrate that the thermodefect voltage can be as high as 1.7 mV/K for 555-777 defects in semiconducting armchair GNRs. We further investigate the Seebeck coefficient, electrical conductance, and electronic thermal conductance, and also the power factor of the individual junction components to explain the thermodefect effect. Taken together, our study presents a new pathway to enhance the thermoelectric properties of nanomaterials.

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Section: A Vacanciesmentioning

confidence: 93%

Thermodefect voltage in graphene nanoribbon junctions

Aydin,

Sisman,

Fransson

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…For even larger chemical potentials, μ 2 > 0.7 eV, the thermodefect voltage drops substantially for all the three types of longitudinal vacancies and show damped oscillations around zero i.e., both positive and negative voltages are possible for high chemical potentials. These oscillations are associated with the degeneracy effects originated from the Fermi gas properties [11,85,86]. We note here that very high values of the chemical potential, such as >1 eV, are difficult to utilize in practice [37] and values larger than 2.5 eV even falls outside the validity of the tight-binding model [68].…”

Section: Vacanciesmentioning

confidence: 99%

Thermodefect voltage in graphene nanoribbon junctions

Aydin

Şişman

Fransson

et al. 2022

J. Phys.: Condens. Matter

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Thermoelectric junctions are often made of components of different materials characterized by distinct transport properties. Single material junctions, with the same type of charge carriers, have also been considered to investigate various classical and quantum effects on the thermoelectric properties of nanostructured materials. We here introduce the concept of defect-induced thermoelectric voltage, namely, thermodefect voltage, in graphene nanoribbon (GNR) junctions under a temperature gradient. Our thermodefect junction is formed by two GNRs with identical properties except the existence of defects in one of the nanoribbons. At room temperature the thermodefect voltage is highly sensitive to the types of defects, their locations, as well as the width and edge configurations of the GNRs. We computationally demonstrate that the thermodefect voltage can be as high as 1.7 mV/K for 555-777 defects in semiconducting armchair GNRs. We further investigate the Seebeck coefficient, electrical conductance, and electronic thermal conductance, and also the power factor of the individual junction components to explain the thermodefect effect. Taken together, our study presents a new pathway to enhance the thermoelectric properties of nanomaterials.

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“…internal energy [25], conductance [22]) and oscillatory characteristics of others (e.g. specific heat [25][26][27][28][29], thermopower [30,31]) appear due to the nature of Fermi-Dirac distribution function and its derivative with respect to energy (so called occupancy variance or thermal broadening function) respectively [32][33][34]. Size-dependent quantum oscillations attracted a great deal of interest particularly in recent decades [6,[8][9][10][11][12][13][14][15]35].…”

Section: Introductionmentioning

confidence: 99%

Quantum shape oscillations in the thermodynamic properties of confined electrons in core–shell nanostructures

Aydin¹,

Fransson²,

Şişman³

2021

J. Phys.: Condens. Matter

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Quantum shape effect appears under the size-invariant shape transformations of strongly confined structures. Such a transformation distinctively influences the thermodynamic properties of confined particles. Due to their characteristic geometry, core–shell nanostructures are good candidates for quantum shape effects to be observed. Here we investigate the thermodynamic properties of non-interacting degenerate electrons confined in core–shell nanowires consisting of an insulating core and a GaAs semiconducting shell. We derive the expressions of shape-dependent thermodynamic quantities and show the existence of a new type of quantum oscillations due to shape dependence, in chemical potential, internal energy, entropy and specific heat of confined electrons. We provide physical understanding of our results by invoking the quantum boundary layer concept and evaluating the distributions of quantized energy levels on Fermi function and in state space. Besides the density, temperature and size, the shape per se also becomes a control parameter on the Fermi energy of confined electrons, which provides a new mechanism for fine tuning the Fermi level and changing the polarity of semiconductors.

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Quantum oscillations in confined and degenerate Fermi gases. I. Half-vicinity model

Cited by 11 publications

References 42 publications

Thermodefect voltage in graphene nanoribbon junctions

Thermodefect voltage in graphene nanoribbon junctions

Thermodefect voltage in graphene nanoribbon junctions

Quantum shape oscillations in the thermodynamic properties of confined electrons in core–shell nanostructures

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