Ferroelectricity in Free Niobium Clusters
2003; American Association for the Advancement of Science; Volume: 300; Issue: 5623 Linguagem: Inglês
10.1126/science.1083247
ISSN1095-9203
AutoresRamiro Moro, Xiaoshan Xu, Shuangye Yin, Walt A. de Heer,
Tópico(s)Iron-based superconductors research
ResumoElectric deflections of gas-phase, cryogenically cooled, neutral niobium clusters [NbN; number of atoms (N) = 2 to 150, temperature (T) = 20to 300kelvin], measured in molecular beams, show that cold clusters may attain an anomalous component with very large electric dipole moments. In contrast, room-temperature measurements show normal metallic polarizabilities. Characteristic energies kBTG(N) [Boltzmann constant kB times a transition temperature TG(N)] are identified, below which the ferroelectric-like state develops. Generally, TG decreases [110 > TG(N) > 10K] as N increases, with pronounced even-odd alternations for N > 38. This new state of metallic matter may be related to bulk superconductivity.
Referência(s)