Simon Shahar, Yerzhakov Hennadii, K P Sajilesh, Vakahi Atzmon, Remennik Sergei, Ruhman Jonathan, Khodas Maxim, Millo Oded, Steinberg Hadar
The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, Israel.
The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel.
Nat Commun. 2024 Nov 30;15(1):10439. doi: 10.1038/s41467-024-54517-2.
In metallic transition metal dichalcogenides (TMDs), which remain superconducting down to single-layer thickness, the critical temperature T decreases for Nb-based, and increases for Ta-based materials. This contradicting trend is puzzling, impeding the development of a unified theory. Here we study the thickness-evolution of superconducting tunneling spectra in TaSheterostructures. The upper critical field H is strongly enhanced towards the single-layer limit - following . The same ratio holds for the entire family of intrinsically metallic 2H-TMDs, covering 4 orders of magnitude in H. Using Gor'kov's theory, we calculate the suppression of T by the competing charge density wave (CDW) order, which affects the quasiparticle density of states and the resulting T and H. The latter is found to be universally enhanced by two orders of magnitude. Our results substantiate CDW as the key determinant factor limiting T across the TMD family.
在金属性过渡金属二硫属化物（TMDs）中，即使降至单层厚度仍保持超导性，对于基于Nb的材料，临界温度T降低，而对于基于Ta的材料，临界温度T升高。这种相互矛盾的趋势令人困惑，阻碍了统一理论的发展。在此，我们研究了TaS异质结构中超导隧穿光谱随厚度的演化。上临界场H朝着单层极限强烈增强——遵循 。对于本征金属性的2H-TMDs整个家族，相同的比例关系成立，涵盖了H的4个数量级。利用戈尔科夫理论，我们计算了由竞争电荷密度波（CDW）序对T的抑制，这会影响准粒子态密度以及由此产生的T和H。发现后者普遍增强了两个数量级。我们的结果证实了CDW是限制整个TMD家族T的关键决定因素。
