Magnetoresistance (MR), a change of electrical resistance in response to an external magnetic field, revolutionizes the fundamental study of spintronics and leads to applications in solid-state memory devices. Tungsten ditelluride (WTe₂) exhibits an extremely large MR below 10 K and is highlighted to explore unique properties at high temperatures, such as ferroelectricity at 300 K and the quantum spin Hall effect at 100 K. However, these remarkable phenomena only appear in the exfoliated crystals protected by h-BN encapsulation. Here, an enhanced MR is demonstrated in the synthesized WTe₂ single crystals. The high crystallinity and tunable thickness of the WTe₂ single crystals are achieved by promoter-assisted chemical vapor deposition. The MR of WTe₂ shows a nonsaturating behavior with a positive MR of ∼2000% at 2 K. A large MR of ∼50% is observed at 80 K in the as-grown single crystals, which is comparable to that of bulk WTe₂ and experimentally achieved for the first time. Moreover, the MR is further enhanced by fluoropolymer encapsulation, which effectively induces p-doping in WTe₂ for promoting carrier compensation. This work indicates the synthesized WTe₂ single crystals as a promising candidate for next-generation spintronics devices.

中文翻译：

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掺杂 WTe2 单晶的增强磁阻

磁阻 (MR) 是一种响应外部磁场的电阻变化，它彻底改变了自旋电子学的基础研究，并导致在固态存储设备中的应用。二碲化钨 (WTe ₂ ) 在 10 K 以下表现出极大的 MR，并强调探索高温下的独特性质，例如 300 K 的铁电性和 100 K 的量子自旋霍尔效应。然而，这些显着现象仅出现在由 h-BN 封装保护的剥离晶体。这里，在合成的WTe ₂单晶中展示了增强的MR。WTe ₂单晶的高结晶度和可调厚度是通过促进剂辅助化学气相沉积实现的。WTe的MR_图2显示了非饱和行为，在 2 K 时正 MR 为 ～2000%。在 80 K 时，在生长的单晶中观察到了 ～50% 的大 MR，这与块状 WTe ₂相当，并通过实验实现了第一次。此外，通过氟聚合物封装进一步增强了MR，这有效地诱导了WTe ₂中的p掺杂以促进载流子补偿。这项工作表明合成的WTe ₂单晶是下一代自旋电子器件的有希望的候选者。