Dispersing inorganic colloidal nanoparticles within nematic liquid crystals provides a versatile platform both for forming new soft matter phases and for predefining physical behavior through mesoscale molecular-colloidal self-organization. However, owing to formation of particle-induced singular defects and complex elasticity-mediated interactions, this approach has been implemented mainly just for colloidal nanorods and nanoplatelets, limiting its potential technological utility. Here, orientationally ordered nematic colloidal dispersions are reported of pentagonal gold bipyramids that exhibit narrow but controlled polarization-dependent surface plasmon resonance spectra and facile electric switching. Bipyramids tend to orient with their C₅ rotation symmetry axes along the nematic director, exhibiting spatially homogeneous density within aligned samples. Topological solitons, like heliknotons, allow for spatial reorganization of these nanoparticles according to elastic free energy density within their micrometer-scale structures. With the nanoparticle orientations slaved to the nematic director and being switched by low voltages ≈1 V within a fraction of a second, these plasmonic composite materials are of interest for technological uses like color filters and plasmonic polarizers, as well as may lead to the development of unusual nematic phases, like pentatic liquid crystals.

中文翻译：

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胶体金双锥体的向列顺序、等离子转换和自构图

在向列液晶中分散无机胶体纳米粒子为形成新的软物质相和通过中尺度分子胶体自组织预定义物理行为提供了一个多功能平台。然而，由于形成粒子诱导的奇异缺陷和复杂的弹性介导的相互作用，这种方法主要仅用于胶体纳米棒和纳米血小板，限制了其潜在的技术实用性。在这里，定向有序的向列胶体分散体报道了五边形金双锥体，其表现出狭窄但受控的偏振相关表面等离子体共振光谱和容易的电切换。双锥体倾向于以其 C ₅定向沿向列导向器的旋转对称轴，在对齐的样品中表现出空间均匀的密度。拓扑孤子，如螺旋波，允许这些纳米粒子根据其微米级结构内的弹性自由能密度进行空间重组。随着纳米粒子方向从属于向列导向器并在几分之一秒内通过约 1 V 的低电压切换，这些等离子体复合材料对滤色器和等离子体偏振器等技术用途很感兴趣，并可能导致发展不寻常的向列相，如五元液晶。