The properties and characteristics of thin-film materials strongly depend on their textures and orientations. However, the attainable film morphologies are severely limited by substrates and growth thermodynamics. Metastable films that otherwise cannot be grown by conventional growth methods may overcome these limitations, thus allowing a dramatic expansion of the spectrum of film textures and orientations. Here we present a means to grow metastable platinum layers that are deposited from platinum alloyed with bismuth surfactant material. This is distinct from conventional surfactant-aided growth of films in which surfactants are typically deposited onto the substrate before film deposition, altering the film growth mode but not the film morphology by tuning the surface energy. Surprisingly, we find that almost no bismuth is incorporated into the platinum layer, but rather the structural morphology of this layer is significantly altered. When this metastable platinum layer is applied to spin-orbit-torque technology, a huge increase in the current-driven velocity of chiral domain walls in perpendicularly magnetized wire on top of the metastable platinum layer is observed for otherwise the same current density, while the platinum resistivity is found to barely increase. Our findings show that the metastable film grown from material alloyed with surfactant is promising for the development of devices in various fields, such as spintronics, semiconductors, and quantum materials.

中文翻译：

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亚稳态铂膜中自旋轨道转矩驱动的高效手性-域壁运动

薄膜材料的性质和特性在很大程度上取决于其纹理和方向。但是，可获得的薄膜形态受到基材和生长热力学的严重限制。否则无法通过常规生长方法生长的亚稳膜可以克服这些局限性，从而可以大大扩展膜的质地和取向范围。在这里，我们提出一种方法来生长由与铋表面活性剂材料合金化的铂沉积的亚稳态铂层。这与常规的表面活性剂辅助的膜生长不同，在常规的表面活性剂辅助的膜生长中，通常在膜沉积之前将表面活性剂沉积在基材上，从而通过调节表面能来改变膜的生长模式，而不改变膜的形态。出奇，我们发现几乎没有铋被掺入铂层中，但是该层的结构形态却发生了显着变化。当将此亚稳铂层应用于自旋-轨道-扭矩技术时，观察到在亚稳铂层顶部的垂直磁化线中，手性畴壁的电流驱动速度大大提高，否则电流密度相同，而发现铂电阻率几乎没有增加。我们的发现表明，由与表面活性剂合金化的材料所形成的亚稳膜对于自旋电子学，半导体和量子材料等各个领域的器件开发具有广阔的前景。当将此亚稳铂层应用于自旋-轨道-扭矩技术时，观察到在亚稳铂层顶部的垂直磁化线中，手性畴壁的电流驱动速度大大提高，否则电流密度相同，而发现铂电阻率几乎没有增加。我们的发现表明，由与表面活性剂合金化的材料所形成的亚稳膜对于自旋电子学，半导体和量子材料等各个领域的器件开发具有广阔的前景。当将此亚稳铂层应用于自旋-轨道-扭矩技术时，观察到在亚稳铂层顶部的垂直磁化线中，手性畴壁的电流驱动速度大大提高，否则电流密度相同，而发现铂电阻率几乎没有增加。我们的发现表明，由与表面活性剂合金化的材料所形成的亚稳膜对于自旋电子学，半导体和量子材料等各个领域的器件开发具有广阔的前景。