Phase-change materials serve a broad field of applications ranging from non-volatile electronic memory to optical data storage by providing reversible, repeatable, and rapid switching between amorphous and crystalline states accompanied by large changes in the electrical and optical properties. Here, we demonstrate how ion irradiation can be used to tailor disorder in initially crystalline Ge₂Sb₂Te₅ (GST) thin films via the intentional creation of lattice defects. We found that continuous Ar⁺-ion irradiation at room temperature of GST films causes complete amorphization of GST when exceeding 0.6 (for rock-salt GST) and 3 (for hexagonal GST) displacements per atom (n_dpa). While the transition from rock-salt to amorphous GST is caused by progressive amorphization via the accumulation of lattice defects, several transitions occur in hexagonal GST upon ion irradiation. In hexagonal GST, the creation of point defects and small defect clusters leads to the disordering of intrinsic vacancy layers (van der Waals gaps) that drives the electronic metal–insulator transition. Increasing disorder then induces a structural transition from hexagonal to rock-salt and then leads to amorphization. Furthermore, we observed different annealing behavior of defects for rock-salt and hexagonal GST. The higher amorphization threshold in hexagonal GST compared to rock-salt GST is caused by an increased defect-annealing rate, i.e., a higher resistance against ion-beam-induced disorder. Moreover, we observed that the recovery of defects in GST is on the time scale of seconds or less at room temperature.

中文翻译：

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室温下 Ge2Sb2Te5 薄膜中离子辐照诱导缺陷的快速恢复

相变材料通过在非晶态和晶态之间提供可逆、可重复和快速切换，伴随着电学和光学特性的巨大变化，服务于从非易失性电子存储器到光学数据存储的广泛应用领域。在这里，我们展示了如何通过有意创建晶格缺陷，使用离子辐射来调整初始结晶 Ge ₂ Sb ₂ Te ₅ (GST) 薄膜中的无序。我们发现，连续的Ar ⁺超过0.6（为岩盐GST）和3（对于六角形GST）每原子位移（ -离子时在照射GST膜的室温引起的GST完整非晶Ñ _DPA）。虽然从岩盐到非晶 GST 的转变是由通过晶格缺陷积累的渐进非晶化引起的，但在离子照射下六方 GST 中会发生几种转变。在六边形 GST 中，点缺陷和小缺陷簇的产生导致本征空位层（范德华间隙）的无序，从而驱动电子金属-绝缘体转变。增加无序然后诱导从六边形到岩盐的结构转变，然后导致非晶化。此外，我们观察到岩盐和六边形 GST 缺陷的不同退火行为。与岩盐 GST 相比，六方 GST 中更高的非晶化阈值是由增加的缺陷退火率引起的，即对离子束引起的无序具有更高的抵抗力。而且，