Semimetal

Figure Al.3.8. Schematic energy bands illustrating an insulator (large band gap), a semiconductor (small band gap), a metal (no gap) and a semimetal. In a semimetal, one band is almost filled and another band is almost empty.

Parent D C and Anderson S L 1992 Chemistry of metal and semimetal cluster ions Chem. Rev. 92 1541... 

Figure C2.15.7. Generic band diagrams insulator, metal, semimetal, and semiconductor.

Pankove J I and Moustaka T D 1997 Gallium Nitride (Semiconductors and Semimetals 50) (Boston Academic)... 

Kaneda T 1985 Lightwave Communications Technology (Semiconductor and Semimetals 22D) ed WT Tsang (Orlando, FL Academic)... 

Miscellaneous. Reductioa of a palladium salt by CO is the basis of a visual test for ambieat carboa moaoxide (227). Palladium compouads are used as photographic seasitizers (228). The low dimensional mixed valeace compouad Csq g3[Pd(S2C2(CN)2)] 0.5H2O behaves as a semimetal at room temperature (229). Palladium compouads isostmctural with poteat platiaum antitumor compounds have poor antitumor activity (230). 

The negative electron and light hole masses Hsted for HgTe are a consequence of its being a semimetal rather than semiconductor. The curvatures of these two bands are inverted with respect to the convention defined for semiconductors. 

After the mid-1970s, the downsizing of North American vehicles and the introduction of front wheel drive vehicles brought about the widespread usage of a new class of friction materials (4) called semimetallics, also called semimets and carbon—metaUics. Because of the allegedly adverse health effects associated with asbestos [1332-21 -4] (qv) fibers, a second new class of friction materials called nonasbestos organics (NAOs) came about (5). Such materials are called either asbestos-free or nonasbestos friction materials (2). 

Since then, STM has been established as an insttument fot foteftont research in surface physics. Atomic resolution work in ultrahigh vacuum includes studies of metals, semimetals and semiconductors. In particular, ultrahigh-vacuum STM has been used to elucidate the reconstructions that Si, as well as other semiconducting and metallic surfaces undergo when a submonolayer to a few monolayers of metals are adsorbed on the otherwise pristine surface. ... 

H. B. Bebb and E. W. Williams, in Semiconductors and Semimetals. (R. K. Willardson and A. C. Beers, eds.) Academic Press, vol. 8, 1972. An extensive review of PL theory and technique, with emphasis on semiconductors. Some of the experimental aspects and examples are becoming outdated. 

The measured magnetic susceptibility of multilayer buckytubes for xb S approximately half xg of graphite. This can be interpreted as follows. We recall that crystalline graphite is a semimetal with a small band overlap and a low density of carriers (10 /cm )[33, 34] the in-plane effective mass is small (rn ... 

Theory predicts that buckytubes can either be metals, semimetals, or semiconductors, depending on diameter and degree of helicacy. The purpose of our study is to give a preliminary answer to this question. A detailed analysis has been published elsewhere[39]. In this section, we present mainly experimental results. 

Song et al. [16] reported results relative to a four-point resistivity measurement on a large bundle of carbon nanotubes (60 um diameter and 350 tm in length between the two potential contacts). They explained their resistivity, magnetoresistance, and Hall effect results in terms of a conductor that could be modeled as a semimetal. Figures 4 (a) and (b) show the magnetic field dependence they observed on the high- and low-temperature MR, respectively. 

In order to discuss electron transport properties we need to know about the electronic distribution. This means that, for the case of metals and semimetals, we must have a model for the Fermi surface and for the phonon spectrum. The electronic structure is discussed in Chap. 5. We also need to estimate or determine some characteristic lengths. 

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