ISSN:
1432-0630
Keywords:
PACS: 61.16.Ch; 61.72.Ff; 72.10.Fk
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
2 and 1T-TaSe2were probed by variable temperature UHV-STM. In 1T-TaS2, which indicates a metal-Mott insulator transition at 180 K, the impurity image varied drastically depending on its electronic structure: in its metallic phase, defects were imaged as less-conducting regions with a lateral size of ∼2 nm, while in the insulating phase spherically oscillating structures were frequently found (Friedel oscillation). The dimensions of oscillation, being ∼15 nm in period and ∼1 nm in amplitude, were substantially larger than those reported in normal metals. On the other hand, the 1T-TaSe2 crystals examined here showed both metallic and insulating behavior at room temperature, depending on their surface conditions. The enhanced Friedel oscillation was encountered only on the insulating surfaces. These observations are consistent with the theoretical model proposed by Kobayashi, in which low-energy excitations with small wavenumbers play an important role in enhancing the Friedel oscillation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003390051125
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