Nernst effect

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In physics and chemistry, the Nernst effect (also termed first Nernst–Ettingshausen effect, after Walther Nernst and Albert von Ettingshausen) is a thermoelectric (or thermomagnetic) phenomenon observed when a sample allowing electrical conduction is subjected to a magnetic field and a temperature gradient normal (perpendicular) to each other. An electric field will be induced normal to both.

This effect is quantified by the Nernst coefficient , which is defined to be

where is the y-component of the electric field that results from the magnetic field's z-component and the x-component of the temperature gradient .

The reverse process is known as the Ettingshausen effect and also as the second Nernst–Ettingshausen effect.

Physical picture[edit]

Mobile energy carriers (for example conduction-band electrons in a semiconductor) will move along temperature gradients due to statistics[dubious ] and the relationship between temperature and kinetic energy. If there is a magnetic field transversal to the temperature gradient and the carriers are electrically charged, they experience a force perpendicular to their direction of motion (also the direction of the temperature gradient) and to the magnetic field. Thus, a perpendicular electric field is induced.

Sample types[edit]

Semiconductors exhibit the Nernst effect. This has been studied in the 1950s by Krylova, Mochan and many others. In metals however, it is almost non-existent. It appears in the vortex phase of type-II superconductors due to vortex motion. This has been studied by Huebener et al. High-temperature superconductors exhibit the Nernst effect both in the superconducting and in the pseudogap phase, as was first found by Xu et al. Heavy-Fermion superconductors can show a strong Nernst signal which is likely not due to the vortices, as was found by Bel et al.

See also[edit]

Journal articles[edit]

  • Bel, R.; Behnia, K.; Nakajima, Y.; Izawa, K.; Matsuda, Y.; Shishido, H.; Settai, R.; Onuki, Y. (2004). "Giant Nernst Effect in CeCoIn5". Physical Review Letters. 92 (21): 217002. arXiv:cond-mat/0311473. Bibcode:2004PhRvL..92u7002B. doi:10.1103/PhysRevLett.92.217002. PMID 15245310. S2CID 119337785.
  • Huebener, R. P.; Seher, A. (10 May 1969). "Nernst Effect and Flux Flow in Superconductors. I. Niobium". Physical Review. 181 (2): 701–709. doi:10.1103/PhysRev.181.701.
  • Huebener, R. P.; Seher, A. (10 May 1969). "Nernst Effect and Flux Flow in Superconductors. II. Lead Films". Physical Review. 181 (2): 710–716. doi:10.1103/PhysRev.181.710.
  • Krylova, T. V.; Mochan, I. V. (1955). "Investigation of the Nernst Effect of Germanium". J. Tech. Phys. (USSR). 25: 2119.
  • Rowe, V. A.; Huebener, R. P. (10 September 1969). "Nernst Effect and Flux Flow in Superconductors. III. Films of Tin and Indium". Physical Review. 185 (2): 666–671. doi:10.1103/PhysRev.185.666.
  • Xu, Z. A.; Ong, N. P.; Wang, Y.; Kakeshita, T.; Uchida, S. (2000). "Vortex-like excitations and the onset of superconducting phase fluctuation in underdoped La2−xSrxCuO4". Nature. 406 (6795): 486–488. Bibcode:2000Natur.406..486X. doi:10.1038/35020016. PMID 10952303. S2CID 205007888.