Criteria for physical domains in laboratory and solid-state plasmas

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Abstract
Physical domains relevant to laboratory and solid-state plasmas are described in terms of relevant characteristic parameters. Strongly- and weakly-coupled classical plasmas are divided according to the plasma parameter Γ, whereas quantum and classical domains are separated according to the thermal DeBroglie wavelength Λ, nondimensionalized through mean interparticle spacing. These parameters are found to obey the relation Λ2=(π/16)1/3(kBT/R*)Γ4/3, where T is temperature and the Rydberg constant R* includes the dielectric constant of the medium and effective mass of charge carriers. The weakly-coupled degenerate plasma is described in terms of the quantum compression parameter rs, which represents interparticle spacing measured in Bohr radii. An alternative description of this domain is given in terms of a new quantum parameter (labeled ΓQ) whose definition includes the Thomas–Fermi screening length in place of the Debye length in the classical plasma parameter. A graphical display in terms of appropriately nondimensionalized particle number density and temperature, respectively, reveals that all nonrelativistic, nonmagnetic plasma domains are included over the unit area of this graph. Application of these findings is made to GaAs and InP at 300 and 1000 °K in the intrinsic domain. Incorporating recent empirical expressions for effective mass, energy gap, and Fermi energy, it is found that at the lower temperature, the conducting solid-state plasmas of these semiconductors are weakly coupled and classical. At the higher temperature, due primarily to increased carrier concentration, the plasmas grow degenerate.