Low-temperature phonon conductivity results of compensated semiconductors such as Ge(P,Ga), Ge(As,Ga), and Ge(Sb,In) have been for the first time interpreted quantitatively on the basis of the theory proposed by Griffin and Carruthers and extended by Kwok. The compensated Ge samples are designated as Ge(donor impurity, compensating acceptor impurity). The basis of the present interpretations are the complete expressions obtained by Suzuki and Mikoshiba in the light of Kwok's theory for the resonance-scattering relaxation rates of phonons by bound donor electrons in Ge. The elastic and inelastic scatterings, both from the donor-electron singlet ground state and the next higher-energy triplet state, separated by $4\Delta$, as well as phonon-assisted absorption processes are considered in the present calculations in the temperature range 1-4°K. The effect of compensation by acceptor impurities such as Ga in the case of P- and As-doped ($n$-type) Ge and by indium in the case of Sb-doped Ge is reflected in the variations of $4\Delta$ and the donor-electron radius $a_0$. Compensation in the case of P- and As-doped Ge by gallium reduces the values of $4\Delta$ but it almost remains unaffected in the case of Sb-doped Ge when it is compensated by indium. However, the donor-electron radius is reduced in all the cases on compensation.

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