Impurity Band Conduction in HgTe. II. Theoretical Analysis

Abstract

The impurity band conduction in HgTe is analysed. The electrical conduction in low magnetic field is described in short mean free path approximation. The impurity concentration is estimated by the analysis of the electrical conduction versus magnetic field. The electrons and holes in the impurity band are qualitatively described as carriers from different parts of the impurity band.

Analysis of the electrical conduction in CdHgTe crystals

“…Four types of electrical conduction: n-type, p-like, p-type, and intrinsic are well defined with the use of this model. The model has been described in 117, 23,431. To calculate the electrical conduction one ought to know the impurity band structure (not known), conduction and valence band structure These types of impurity states have been called "amphoteric" states [43].…”

“…As a comment to this problem one can point out the similarity between A, 8H and the I B conduction in HgTe [23]. The conductivity of low-mobility carriers A is about ten times larger than 8H and is independent of the magnetic field in the range in which 8H shows strong variation, just like the behaviour of the I B conduction in HgTe which is shown in [23]. It has been shown in [23] that the shape of 6H seen in Fig.…”

“…The resonant scattering of the conduction band electrons [l6], the modification of the density of states [26,27], and the impurity band conduction [20, 28,291 were described in 1972 as effects of the resonant states. The three types of electric carriers have been ascribed to the conduction band CB, valence band VB, and impurity band IB [20,23]. However, the model including three types of carriers is sometimes neglected in the analysis with respect to the method of the determination of the carrier parameters as well as to description of their nature 128 t o 36, 441.…”

High Magnetic Field Transport in II–VI Heterostructures

“…For bulk sampies of HgTe, multiple-carrier models using up to four different carrier types at low temperatures have been employed [4,5,6], where the parameters were determined by fitting. As an alternative method we use the mobility-conductivity-analysis instead of a multi-carrier fit [3].…”

“…By tilted field measurements the oscillating carriers were found to be two-dimensional. Because the oscillation pattern looks as if only one occupied subband is involved the data was fit ted to the oscillation equation (5) but additionally the effect of the field modulation was included. This fit allowed the parameters listed in table 2 to be determined.…”