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arXiv 1203.2628cond-mat.str-elcond-mat.mes-hall
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强无序下拓扑绝缘体表面态的命运

The fate of topological-insulator surface states under strong disorder

Gerald Schubert, Holger Fehske, Lars Fritz, Matthias Vojta

摘要:

三维拓扑绝缘体的特征是Dirac类表面状态,其在拓扑上被保护免受弱淬火无序的影响。在这里,我们调查的影响,表面无序超出弱无序限制,使用大规模的数值模拟。我们发现两个定性不同的制度:中度无序破坏狄拉克锥,并诱导扩散金属行为的表面。更值得注意的是,对于强表面无序,狄拉克锥重新出现,因为新的弱无序“表面”状态出现在无序表面层下的样品中,这可以理解为拓扑绝缘体和安德森绝缘体之间的界面。总之,这表明了拓扑表面状态的无序的剧烈影响,这不能单独在有效的二维模型的表面状态。

英文摘要:

Three-dimensional topological insulators feature Dirac-like surface states which are topologically protected against the influence of weak quenched disorder. Here we investigate the effect of surface disorder beyond the weak-disorder limit using large-scale numerical simulations. We find two qualitatively distinct regimes: Moderate disorder destroys the Dirac cone and induces diffusive metallic behavior at the surface. Even more remarkably, for strong surface disorder a Dirac cone reappears, as new weakly disordered "surface" states emerge in the sample beneath the disordered surface layer, which can be understood in terms of an interface between a topological and an Anderson insulator. Together, this demonstrates the drastic effect of disorder on topological surface states, which cannot be captured within effective two-dimensional models for the surface states alone.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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