近日,美国麻省理工学院的J. G. Checkelsky及其研究团队取得一项新进展。经过不懈努力,他们揭示结构调制超晶格中条纹电子相的证据。相关研究成果已于2024年7月3日在国际权威学术期刊《自然》上发表。
该研究团队报道了块体vdW超晶格SrTa2S5实现了二维过渡金属二硫化物(TMD) H-TaS2层的不相称的一维(1D)结构调制。量子振荡证明了H-TaS2层中的高质量电子输运通过调制变得各向异性,并表现出与光刻调制的二维系统平行的可通约振荡。研究人员还发现SrTa2S5中非常规的、干净极限的超导性,相对于层内相干性,层间相干性明显受到抑制。
层间临界电流的面内磁场依赖性以及结构调制的电子衍射表明,SrTa2S5的超导性是空间调制的,并且在相邻的TMD层之间不匹配。SrTa2S5的现象学暗示了配对密度波超导性,可能为微观评价这种非常规序提供了一种途径。更广泛地说,SrTa2S5建立了块体vdW超晶格作为通用平台,以解决围绕纳米级vdW器件到宏观晶体形式的调制电子相的长期预测。
据悉,晶体的电子特性可以通过叠加空间周期性电、磁或结构调制来控制。与原子晶格不相称的长波调制特别有趣,最近二维(2D)莫尔材料的进展就是一个例子。块体范德华(vdW)超晶格承载了最小无序层之间的二维界面,代表了人工vdW异质结构的可扩展块体类似物,并提供了探索不相关调制二维状态的补充场所。
附:英文原文
Title: Evidence of striped electronic phases in a structurally modulated superlattice
Author: Devarakonda, A., Chen, A., Fang, S., Graf, D., Kriener, M., Akey, A. J., Bell, D. C., Suzuki, T., Checkelsky, J. G.
Issue&Volume: 2024-07-03
Abstract: The electronic properties of crystals can be manipulated by superimposing spatially periodic electric, magnetic or structural modulations. Long-wavelength modulations incommensurate with the atomic lattice are particularly interesting, exemplified by recent advances in two-dimensional (2D) moiré materials. Bulk van der Waals (vdW) superlattices hosting 2D interfaces between minimally disordered layers represent scalable bulk analogues of artificial vdW heterostructures and present a complementary venue to explore incommensurately modulated 2D states. Here we report the bulk vdW superlattice SrTa2S5 realizing an incommensurate one-dimensional (1D) structural modulation of 2D transition metal dichalcogenide (TMD) H-TaS2 layers. High-quality electronic transport in the H-TaS2 layers, evidenced by quantum oscillations, is made anisotropic by the modulation and exhibits commensurability oscillations paralleling lithographically modulated 2D systems. We also find unconventional, clean-limit superconductivity in SrTa2S5 with a pronounced suppression of interlayer relative to intralayer coherence. The in-plane magnetic field dependence of interlayer critical current, together with electron diffraction from the structural modulation, suggests superconductivity in SrTa2S5 is spatially modulated and mismatched between adjacent TMD layers. With phenomenology suggestive of pair-density wave superconductivity, SrTa2S5 may present a pathway for microscopic evaluation of this unconventional order. More broadly, SrTa2S5 establishes bulk vdW superlattices as versatile platforms to address long-standing predictions surrounding modulated electronic phases in the form of nanoscale vdW devices to macroscopic crystals.
DOI: 10.1038/s41586-024-07589-5
Source: https://www.nature.com/articles/s41586-024-07589-5
Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html