ABSTRACT
A number of crystals with many atoms in the unit cell show unusual dependence of the crystal lattice
thermal conductivity ðl
Þ on temperature.
In this case, in the low-temperature region, the thermal
conductivity of these crystals has a maximum and is atypical for crystals, which have a small number of
atoms in the unit cell. In the high-temperature region, the lattice thermal conductivity depends weakly on
temperature, and there is a wide plateau characteristic of amorphous solids. In Figure 6.1 the temperature
dependencies of l
are shown for a number of crystals having many atoms in the unit cell. Figure 6.1
shows that in some cases amorphous behavior of thermal conductivity in crystals having many atoms in
the unit cell, or with very heavy unit cell, begins from very low temperature. The influence of the unit cell
size on the lattice thermal conductivity can be studied more precisely when analyzing the temperature
dependencies of l
in various modifications of boron and its crystal-chemical analogues, where rigid
icosahedral structure takes place and the character of chemical bonding varies slightly.
