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Patterning of the two-dimensional electron gas formed at the interface of two band insulators such as LaAlO₃/SrTiO₃ is one of the key challenges in oxide electronics. The use of energetic ion beam exposure for engineering the interface conductivity has been investigated. We found that this method can be utilized to manipulate the conductivity at the LaAlO₃/SrTiO₃ interface by carrier localization, arising from the defects created by the ion beam exposure, eventually producing an insulating ground state. This process of ion-beam-induced defect creation results in structural changes in SrTiO₃ as revealed by the appearance of first-order polar TO₂ and TO₄ vibrational modes which are associated with Ti–O bonds in the Raman spectra of the irradiated samples. Furthermore, significant observation drawn from the magnetotransport measurements is that the irradiated (unirradiated) samples showed a negative (positive …