Study of Point Defects in Silicon by Means of Positron Annihilation with Core Electrons

Preferential Positron Annihilation in Binary Alloys

“…In our previous studies [2,3] we emphasised the effect of the volume dependence of the annihilation rate when evaluating the PPA. Here we use the well known Brandt and Reinheimer formula [10] (λ = 2 + 134n_ (λ is in ns -1 and n-in atomic units, a.u.))…”

“…To examine the PPA in the Sn-In system, we performed a set of theoretical calculations at a constant atomic volume [2]. Here we choose the Sn atomic volume and expect that the results obtained are very similar for other volumes as the dependence of the volume on the concentration is rather weak (see the inset in Fig.…”

“…Here we use the well known Brandt and Reinheimer formula [10] (λ = 2 + 134n_ (λ is in ns -1 and n-in atomic units, a.u.)) to estimate the volume dependence of the annihilation rate in Sn-In alloys (see [2,3] for details). The result of this procedure is also shown in Fig.…”

“…The influence of the change of the atomic volume with the alloy composition was already mentioned above. Even if such an effect may be neglected (as in the Sn-In case) and the concentration dependence of the annihilation rate does deviate from the straight line (see [2,3]), it is still not clear at which sites the PPA occurs and a theoretical analysis of the contributions of alloy constituents to the total annihilation rate has to be done. Possible positron traps represent a further important point as their influence should be excluded from resulting experimental annihilation rates, which may not be always possible [8].…”

“…In our previous papers we studied preferential positron annihilation in Fe-Al [2] and Mg-Cd [3] systems. Here we present preliminary theoretical and experimental results for Sn-In alloys and discuss them together with results previously found in Fe-Al and Mg-Cd.…”