The interaction of ultrasound with electrons in hybridized states of iron impurity in a mercury selenide crystal

Anomalous low-temperature contribution to the heat capacity from hybridized electronic states on transition element impurities

“…Here we used information from earlier experiments on observing the low-temperature anomalies in various characteristics associated with hybridization of electronic states. [4][5][6]11 In accordance with this information, ⌬ was varied over 3 -5 K during fitting, ⌫ over 30-100 K, and the energy 0 over 5 -15 K. There was some difficulty with the previously undetermined ͑n d / g c ͒. It is easy to obtain a theoretical estimate of this quantity, since the Fermi energy and the concentration of donor electrons are known.…”

“…4,11 Agreement was also obtained on the value of ⌫, which was determined in all the experiments with low precision, since the measured quantities depend relatively weakly on it. The parameter A, which characterizes the electron-electron interaction in hybridized states has been determined here for the first time.…”

Anomalies in the temperature dependence of the contribution to the speed of sound from hybridized electronic states of transition element impurities

“…In writing Eqs. (4) and (5), for the quantities that depend on the energy we replace the Fermi-liquid function with the constants u c and u i for the uniform and localized components and a constant u ic ¼ u ci which describes the coupling of the components. With the above assumptions, Eq.…”

“…3,4 In studies of the propagation of ultrasound, a maximum has been found in the absorption coefficient for the slow wave as a function of temperature, which is explained by the existence of density peak of hybridized states near the Fermi energy. 5 Another acoustic effect that has been detected experimentally is a nonmonotonic dependence of the impurity contribution to the sound speed as a function of temperature within the same low-temperature interval. This effect is studied here.…”