Let us construct the model of metal - element so that external electrons of last layer or sublayers of atomic kernel, left after filling the conduction band, influenced somehow pattern of crystalline structure (for example: for the body-centred lattice - 8 ‘valency’ electrons, and for volume-centered and face-centred lattices - 12 or 9).
ROUGH, QUALITATIVE MEASUREMENT OF NUMBER OF ELECTRONS IN CONDUCTION BAND OF METAL - ELEMENT. EXPLANATION OF FACTORS, INFLUENCING FORMATION OF TYPE OF MONOCRYSTAL MATRIX AND SIGN OF HALL CONSTANT.
(Algorithm of construction of model)
The measurements of the Hall field allow us to determine the sign of charge carriers in the conduction band. One of the remarkable features of the Hall effect is, however, that in some metals the Hall coefficient is positive, and thus carriers in them should, probably, have the charge, opposite to the electron charge /1/. At room temperature this holds true for the following: vanadium, chromium, manganese, iron, cobalt, zinc, circonium, niobium, molybdenum, ruthenium, rhodium, cadmium, cerium, praseodymium, neodymium, ytterbium, hafnium, tantalum, wolfram, rhenium, iridium, thallium, plumbum /2/. Solution to this enigma must be given by complete quantum - mechanical theory of solid body.
Roughly speaking, using the base cases of Born- Karman, let us consider a highly simplified case of one-dimensional conduction band. The first variant: a thin closed tube is completely filled with electrons but one. The diameter of the electron roughly equals the diameter of the tube. With such filling of the area at local movement of the electron an opposite movement of the ‘site’ of the electron, absent in the tube, is observed, i.e. movement of non-negative sighting. The second variant: there is one electron in the tube - movement of only one charge is possible - that of the electron with a negative charge. These two opposite variants show, that the sighting of carriers, determined according to the Hall coefficient, to some extent, must depend on the filling of the conduction band with electrons. Figure 1.
Element | (cubic metres /K) | Z (number) | Z kernel (number) | Lattice type | |
Natrium | Na | -2,30 | 1 | 8 | body-centered |
Magnesium | Mg | -0,90 | 1 | 9 | volume-centered |
Aluminium Or | Al | -0,38 | 2 | 9 | face-centered |
Aluminium | Al | -0,38 | 12 | face-centered | |
Potassium | K | -4,20 | 1 | 8 | body-centered |
Calcium | Ca | -1,78 | 1 | 9 | face-centered |
Calciom | Ca | T=737K | 2 | 8 | body-centered |
Scandium Or | Sc | -0,67 | 2 | 9 | volume-centered |
Scandium | Sc | -0,67 | 1 | 18 | volume-centered |
Titanium | Ti | -2,40 | 1 | 9 | volume-centered |
Titanium | Ti | -2,40 | 3 | 9 | volume-centered |
Titanium | Ti | T=1158K | 4 | 8 | body-centered |
Vanadium | V | +0,76 | 5 | 8 | body-centered |
Chromium | Cr | +3,63 | 6 | 8 | body-centered |
Iron or | Fe | +8,00 | 8 | 8 | body-centered |
Iron | Fe | +8,00 | 2 | 14 | body-centered |
Iron or | Fe | Т=1189K | 7 | 9 | face-centered |
Iron | Fe | Т=1189K | 4 | 12 | face-centered |
Cobalt or | Co | +3,60 | 8 | 9 | volume-centered |
Cobalt | Co | +3,60 | 5 | 12 | volume-centered |
Nickel | Ni | -0,60 | 1 | 9 | face-centered |
Copper or | Cu | -0,52 | 1 | 18 | face-centered |
Copper | Cu | -0,52 | 2 | 9 | face-centered |
Zink or | Zn | +0,90 | 2 | 18 | volume-centered |
Zink | Zn | +0,90 | 3 | 9 | volume-centered |
Rubidium | Rb | -5,90 | 1 | 8 | body-centered |
Itrium | Y | -1,25 | 2 | 9 | volume-centered |
Zirconium or | Zr | +0,21 | 3 | 9 | volume-centered |
Zirconium | Zr | 4 | 8 | body-centered | |
Niobium | Nb | 5 | 8 | body-centered | |
Molybde-num | Mo | +1,91 | 6 | 8 | body-centered |
Ruthenium | Ru | +22 | 7 | 9 | volume-centered |
Rhodium Or | Rh | +0,48 | 5 | 12 | face-centered |
Rhodium | Rh | +0,48 | 8 | 9 | face-centered |
Palladium | Pd | -6,80 | 1 | 9 | face-centered |
Silver or | Ag | -0,90 | 1 | 18 | face-centered |
Silver | Ag | -0,90 | 2 | 9 | face-centered |
Cadmium or | Cd | +0,67 | 2 | 18 | volume-centered |
Cadmium | Cd | +0,67 | 3 | 9 | volume-centered |
Caesium | Cs | -7,80 | 1 | 8 | body-centered |
Lanthanum | La | -0,80 | 2 | 9 | volume-centered |
Cerium or | Ce | +1,92 | 3 | 9 | face-centered |
Cerium | Ce | +1,92 | 1 | 9 | face-centered |
Praseodymium or | Pr | +0,71 | 4 | 9 | volume-centered |
Praseodymium | Pr | +0,71 | 1 | 9 | volume-centered |
Neodymium or | Nd | +0,97 | 5 | 9 | volume-centered |
Neodymium | Nd | +0,97 | 1 | 9 | volume-centered |
Gadolinium or | Gd | -0,95 | 2 | 9 | volume-centered |
Gadolinium | Gd | T=1533K | 3 | 8 | body-centered |
Terbium or | Tb | -4,30 | 1 | 9 | volume-centered |
Terbium | Tb | 2 | 8 | body-centered | |
Dysprosium | Dy | -2,70 | 1 | 9 | volume-centered |
Dysprosium | Dy | 2 | 8 | body-centered | |
Erbium | Er | -0,341 | 1 | 9 | volume-centered |
Thulium | Tu | -1,80 | 1 | 9 | volume-centered |
Ytterbium or | Yb | +3,77 | 3 | 9 | face-centered |
Ytterbium | Yb | +3,77 | 1 | 9 | face-centered |
Lutecium | Lu | -0,535 | 2 | 9 | volume-centered |
Hafnium | Hf | +0,43 | 3 | 9 | volume-centered |
Hafnium | Hf | 4 | 8 | body-centered | |
Tantalum | Ta | +0,98 | 5 | 8 | body-centered |
Wolfram | W | +0,856 | 6 | 8 | body-centered |
Rhenium | Re | +3,15 | 6 | 9 | |
Osmium | Os | <0 | 4 | 12 | volume centered |
Iridium | Ir | +3,18 | 5 | 12 | face-centered |
Platinum | Pt | -0,194 | 1 | 9 | face-centered |
Gold or | Au | -0,69 | 1 | 18 | face-centered |
Gold | Au | -0,69 | 9 | face-centered | |
Thallium or | Tl | +0,24 | 3 | 18 | volume-centered |
Thallium | Tl | +0,24 | 4 | 9 | volume-centered |
Lead | Pb | +0,09 | 4 | 18 | face-centered |
Lead | Pb | +0,09 | 5 | 9 | face-centered |
Where Rh is the Hall’s constant (Hall’s coefficient)