Neutrino-Recoil-Induced Frenkel Pairs in InSb Observed by Mössbauer Spectroscopy

The decay of ${}^{119}$Te to ${}^{119}$Sb via electron capture is utilized to produce isolated, single Frenkel pairs in InSb. This is caused by neutrino emission, which imparts a recoil of 12 eV to the ${}^{119}$Sb atoms, thereby displacing about 20% of them into interstitial sites. The effect is traced by Mössbauer emission spectroscopy following the decay of ${}^{119}$Sb to ${}^{119}$Sn. The displacement threshold $E_d$ is confined to $6<\mathrm{}{E}_d<12\mathrm{}$ eV from auxiliary experiments employing ${}^{119m}\mathrm{Te}$ isotopes.