Charge‐density waves in transition‐metal compounds
APR 01, 1979
At low temperatures some crystals undergo a phase transition to a state in which the electron density displays periodic modulations incommensurate with the crystal lattice.
The vast majority of compounds crystallize into a regular form in which a unit cell is repeated indefinitely, except for generally localized defects, impurities and boundaries. In a few compounds, however, at sufficiently low temperatures interactions between electrons and ions across unit cells make this regular array unstable with respect to small distortions. The stable state is one in which the charge density, the spin density, or the ion positions display long‐period modulations. The period of these modulations may be incommensurate with the spacing of the underlying lattice, so that the material is no longer truly periodic, having two unrelated periods. In this article we shall focus on charge‐density waves, in which the electron density and also the ion positions exhibit a periodic variation.
References
1. J. A. Wilson, F. J. DiSalvo, S. Mahajan, Adv. in Physics 24, 117 (1975); https://doi.org/ADPHAH F. J. Di‐Salvo, in Electron‐Phonon Interactions and Phase Transitions, T. Riste ed., Plenum, New York, (1977).
2. R. Comés, M. Lambert, H. Launois, H. R. Zeller, Phys. Rev. B8, 571 (1973).https://doi.org/PLRBAQ
8. D. E. Moncton, J. D. Axe, F. J. DiSalvo, Phys. Rev. Lett. 34, 734 (1975); https://doi.org/PRLTAO D. E. Moncton, J. D. Axe, F. J. DiSalvo, Phys. Rev. B16, 801 (1977).https://doi.org/PLRBAQ
Technical knowledge and skills are only some of the considerations that managers have when hiring physical scientists. Soft skills, in particular communication, are also high on the list.
Research exchanges between US and Soviet scientists during the second half of the 20th century may be instructive for navigating today’s debates on scientific collaboration.
The Eisenhower administration dismissed the director of the National Bureau of Standards in 1953. Suspecting political interference with the agency’s research, scientists fought back—and won.
Alternative undergraduate physics courses expand access to students and address socioeconomic barriers that prevent many of them from entering physics and engineering fields. The courses also help all students develop quantitative skills.
October 01, 2025 12:00 AM
Get PT in your inbox
Physics Today - The Week in Physics
The Week in Physics" is likely a reference to the regular updates or summaries of new physics research, such as those found in publications like Physics Today from AIP Publishing or on news aggregators like Phys.org.