Percolation phase transition, self-organization processes and thermal conductivity in PbSe_1-xTe_x semiconductor solid solutions at small Te concentration

ABSTRACT

The isotherms of the lattice thermal conductivity λ_L for the PbSe_1-xTe_x semiconductor solid solutions (х = 0–0.045) were obtained in the temperature range T = (200–600) K. The λ_L(x) dependences exhibit a general trend to a decrease in λ_L with increasing x, but the peaks are observed near x = 0.007, 0.015 and 0.0025 indicating the presence of phase transformations. We associated the first peak with a percolation-type phase transition to the impurity continuum and estimated the critical index for λ_L within the framework of dynamic scaling theory. The second and third peaks were attributed to the self-organization processes in the PbSe_1-xTe_x after the percolation threshold reaching. The effective cross-sections σ_s for phonon scattering by impurity (Te) atoms were determined experimentally and calculated theoretically using the Klemens theory. The data obtained are another confirmation of our assumption about the presence of such percolation-type phase transition in any solid solution.

KEYWORDS:

• PbSe_1-xTe_x solid solutions
• percolation phase transition
• self-organization
• thermal conductivity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ministry of Education and Science of Ukraine (Project # M 0625)