Abstract
NEW CRITICAL DENSITY IN METAL-INSULATOR TRANSITION, OBTAINED IN VARIOUS N(P)- TYPE DEGENERATE CRYSTALLINE ALLOYS, BEING JUST THAT OF CARIERS LOCALIZED IN EXPONENTIAL BAND TAILS. (II)
Prof. Dr. Huynh Van Cong*
ABSTRACT
By basing on the same physical model and treatment method, as usedin our recent work (Van Cong, 2024), for[ ]- crystallinealloys, , referred to as (I), we will investigate the criticalimpurity densities in the metal-insulator transition (MIT), obtainednow in n(p)-type degenerate X(x)[ ]- crystallinealloys, being due to the effects of the size of donor (acceptor) d(a)-radius, and the x- concentration, assuming that all the impuritiesare ionized even at T=0 K. In such n(p)-type degenerate X(x) -crystalline alloys, we will determine: (i)-the critical impurity densityin the MIT, as that given in Eq. (8), by using anempirical Mott parameter , and (ii)-the density of electrons (holes) localized inthe exponential conduction (valence)-band tails (EBT),( ), as that given inEq. (26), by using our empirical Heisenberg parameter, , as given in Eq.(15), suggesting that: for given and x,( )obtained with a precision of the order of , as observed in Tables 2-8. In otherwords, such the critical d(a)-density is just the density of electrons (holes) localized in the EBT,. So, if denoting the total impurity densityby N, the effective density of free electrons (holes), given in the parabolic conduction(valence) band of the n(p)-type degenerate - crystalline alloy, can thus be defined, as thecompensated ones, by:, needing todetermine various optical, electrical, and thermoelectric properties in such n(p)-typedegenerate X(x)-crystalline alloys, as those studied in n(p)-type degenerate crystals (VanCong, 2023).
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