An electron-spin resonance technique has been used to examine the influence exerted by the degree of compensation on spin effects in a set of nonmagnetic Ge:As semiconductor samples in the vicinity of the insulator–metal phase transition at temperatures 2 K ≤ T ≤ 80 K. It was found that the behavior of the paramagnetic susceptibility, specific to the Pauli paramagnetism and manifested in the spin density resonance, is drawn deep into the insulator state and is observed up to rather large degrees of compensation K ≈ 0.7 at temperature 20 K ≥ T ≥ 5–10 K. Outside this temperature range, both the quantities rapidly grow with increasing compensation and their behavior approaches the Curie law characteristic of the strong insulator state. The reason for this behavior is that the degeneracy is lifted at high temperatures and, at low temperatures, electron states are localized at the Fermi level as a result of the Coulomb blockade by compensating acceptors of the most closely lying donor states and the resulting formation of a narrow Coulomb band in the metallized impurity band. At temperature T ≥ 5–10 K, the gap is blurred by thermal excitations and has no effect on the manifestation of the Pauli paramagnetism. The behavior of the line width of the electron-spin resonance is determined by the scattering on quasi-stationary electric dipoles created by the Coulomb blockade at low temperatures and by the scattering on phonons at high temperatures. The behavior of the g -factor is qualitatively correlated with the specific features of the paramagnetic susceptibility and spin density: with decreasing temperature it weakly grows in the range of the Pauli paramagnetism and then rapidly increases in the range in which the Coulomb blockade is manifested and a transition occurs to the Curie law. By an analogy with ferromagnetic materials in which such a fast increase in the g -factor is observed, the possibility of a compensation caused ferromagnetic coupling of spins localized on donors. The microscopic model of such a coupling is discussed.

中文翻译：

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补偿对绝缘体-金属相变附近 Ge:As 半导体中低温自旋有序的影响

电子自旋共振技术已被用于检查补偿程度对一组非磁性 Ge:As 半导体样品中的自旋效应的影响，这些样品位于绝缘体 - 金属相变附近，温度为 2 K ≤ T ≤ 80 K. 发现顺磁化率的行为，特定于泡利顺磁性并表现在自旋密度共振中，被深入到绝缘体状态，并在温度 20 K 下观察到相当大的补偿 K ≈ 0.7 ≥ T ≥ 5–10 K。在这个温度范围之外，随着补偿的增加，数量迅速增长，并且它们的行为接近强绝缘体状态的居里定律特征。这种行为的原因是简并性在高温下被解除，而在低温下，作为库仑阻塞的结果，电子态通过补偿最接近的施主态的受主以及由此在金属化杂质带中形成窄库仑带而定域在费米能级。在温度 T ≥ 5-10 K 时，间隙被热激发模糊，对泡利顺磁性的表现没有影响。电子自旋共振线宽的行为由低温下库仑阻塞产生的准静态电偶极子上的散射和高温下声子上的散射决定。g 因子的行为与顺磁化率和自旋密度的具体特征定性相关：随着温度的降低，它在泡利顺磁性范围内弱增长，然后在库仑阻塞出现的范围内迅速增加，并发生向居里定律的转变。通过与观察到 g 因子如此快速增加的铁磁材料类比，补偿的可能性导致定位在施主上的自旋的铁磁耦合。讨论了这种耦合的微观模型。