Helmut Hofmann
- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0016
- Subject:
- Physics, Nuclear and Plasma Physics
The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties ...
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The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties described by the dielectric function, which is analyzed in greater detail, first for the Drude-Lorentz model then for a fully quantal treatment. With increasing volume of the clusters, only bulk properties typical for a metal are important. For smaller systems, quantum size effects come into play. This effect is studied, reporting on microscopic calculations within the jellium model. Of special interest is the damping width, for which finite values are obtained even at small frequencies if the quantal electronic states are treated as being quasi-continuous. This mechanism is often associated with Landau damping known to conserve entropy. The problem related to this fact is examined, together with the analogous one of wall friction in finite nuclei.Less
The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties described by the dielectric function, which is analyzed in greater detail, first for the Drude-Lorentz model then for a fully quantal treatment. With increasing volume of the clusters, only bulk properties typical for a metal are important. For smaller systems, quantum size effects come into play. This effect is studied, reporting on microscopic calculations within the jellium model. Of special interest is the damping width, for which finite values are obtained even at small frequencies if the quantal electronic states are treated as being quasi-continuous. This mechanism is often associated with Landau damping known to conserve entropy. The problem related to this fact is examined, together with the analogous one of wall friction in finite nuclei.
Hiromichi Ohta and Kunihito Koumoto
- Published in print:
- 2012
- Published Online:
- January 2013
- ISBN:
- 9780199584123
- eISBN:
- 9780191745331
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199584123.003.0010
- Subject:
- Physics, Condensed Matter Physics / Materials
Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power ...
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Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power generation materials that can operate at high temperatures on the basis of their potential advantages over heavy metallic alloys in chemical and thermal robustness. This chapter fabricates high quality epitaxial films composed of oxide thermoelectric materials, which are suitable for clarifying the intrinsic properties. It focuses on the thermoelectric properties of two representative oxide epitaxial films, p-type Ca3Co4O9 and n-type SrTiO3, which exhibit the best thermoelectric figures of merit, ZT(=S 2·σT·κ-1, S: Seebeck coefficient, σ: electrical conductivity, κ: thermal conductivity, and T: absolute temperature) among oxide thermoelectric materials reported to date. In addition, it introduces the recently discovered giant S of two-dimensional electrons confined within a unit cell layer thickness (~0.4 nm) of SrTiO3.Less
Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power generation materials that can operate at high temperatures on the basis of their potential advantages over heavy metallic alloys in chemical and thermal robustness. This chapter fabricates high quality epitaxial films composed of oxide thermoelectric materials, which are suitable for clarifying the intrinsic properties. It focuses on the thermoelectric properties of two representative oxide epitaxial films, p-type Ca3Co4O9 and n-type SrTiO3, which exhibit the best thermoelectric figures of merit, ZT(=S 2·σT·κ-1, S: Seebeck coefficient, σ: electrical conductivity, κ: thermal conductivity, and T: absolute temperature) among oxide thermoelectric materials reported to date. In addition, it introduces the recently discovered giant S of two-dimensional electrons confined within a unit cell layer thickness (~0.4 nm) of SrTiO3.
