Excitation Spectra in Crystal Plasticity.
Excitation Spectra in Crystal Plasticity.
复制标题
晶体可塑性中的激发光谱。
DOI：
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发表时间：
2017
影响因子：
8.6
通讯作者：
S. Zapperi
中科院分区：
文献类型：
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作者：
M. Ovaska;Arttu Lehtinen;M. Alava;L. Laurson;S. Zapperi
塑性变形晶体表现出无标度波动，类似于在驱动无序弹性系统中观察到的接近脱剥落，但屈服临界点的性质仍然存在争议。本文研究了位错系的边际稳定性，并计算了其二维和三维的激发谱。我们的结果表明，激发应力的分布中存在一个奇点，即使局部区域不稳定所需的应力，这与在非晶塑性和自旋玻璃中测量到的应力非常相似。这些结果使我们能够理解最近对突发晶体塑性扩展临界的观察，并解释它们是如何起源于激发谱中赝隙的存在。
Plastically deforming crystals exhibit scale-free fluctuations that are similar to those observed in driven disordered elastic systems close to depinning, but the nature of the yielding critical point is still debated. Here, we study the marginal stability of ensembles of dislocations and compute their excitation spectrum in two and three dimensions. Our results show the presence of a singularity in the distribution of excitation stresses, i.e., the stress needed to make a localized region unstable, that is remarkably similar to the one measured in amorphous plasticity and spin glasses. These results allow us to understand recent observations of extended criticality in bursty crystal plasticity and explain how they originate from the presence of a pseudogap in the excitation spectrum.