Električna vodljivost, Hallov koeficijent i termoelektrična snaga ikosaedarskih i-Al 62Cu25.5Fe12.5 i i-Al63Cu25Fe12 kvazikristala

Abstract

The electrical conductivity, Hall coefficient and thermoelectric power of icosahedral i-Al62Cu25.5Fe12.5 quasicrystal samples in the temperature range 2 K - 340 K are measured, and comparison with icosahedral i-Al63Cu25Fe12 quasicrystal samples is made. We have analysed the temperature dependence of the conductivity below 70 K and the results of this analysis are consistent with the predictions of the weak-localisation and the electron-electron interaction theories. The temperature dependence of the electrical conductivity, Hall coefficient and thermoelectric power above 40 K are consistently explained by a two-band model. Although the overlapping of the valence and conduction bands at Fermi level is responsible for the coexistence of both types of carriers, and it enables us to describe quasicrystals as semi-metals, the temperature variation of the electrical conductivity is determined by that of carrier density which makes the situation essentially the same as that in normal semiconductors.Mjerili smo električnu vodljivost, Hallov koeficijent i termoelektričnu snagu uzorka ikosaedarskog kvazikristala i-Al62Cu25.5Fe12.5 u području temperature 2 K – 340 K i usporedili s uzorkom ikosaedarskog kvazikristala i-Al62Cu25.5Fe12.5. Analizirali smo temperaturnu ovisnost električne vodljivosti ispod 70 K i ustanovili da su rezultati u skladu s predviđanjima teorija slabe lokalizacije i međudjelovanja elektronelektron. Ovisnost električne vodljivosti, Hallovog koeficijenta i termoelektrične snage o temperaturi iznad 40 K uspješno se objašnjava modelom dviju vrpci. Iako je predodžba o preklapanju valentne i vodljive vrpce na Fermijevoj razini odgovorna za istovremeno postojanje dviju vrsta nositelja i za opis kvazikristala kao polumetala, temperaturna ovisnost električne vodljivosti je, kao i kod normalnih poluvodiča, određena promjenom gustoće nositelja

    Similar works