A helix of dipoles In magnetic materials, magnetic dipoles typically line up parallel or antiparallel to each other. However, more complex orderings, such as helical, can also occur. Khalyavin et al. found that in the material BiCu0.1Mn6.9O12, a helical order can be formed out of electric rather than magnetic dipoles. The material also harbors an associated structural helical order, which symmetry analysis suggests might be switchable with an applied electric field. Science, this issue p. 680 Light hole doping of the quadruple perovskite BiMn7O12 results in an unusual ordering. Long-range ordering of magnetic dipoles in bulk materials gives rise to a broad range of magnetic structures, from simple collinear ferromagnets and antiferromagnets, to complex magnetic helicoidal textures stabilized by competing exchange interactions. In contrast, dipolar order in dielectric crystals is typically limited to parallel (ferroelectric) and antiparallel (antiferroelectric) collinear alignments of electric dipoles. Here, we report an observation of incommensurate helical ordering of electric dipoles by light hole doping of the quadruple perovskite BiMn7O12. In analogy with magnetism, the electric dipole helicoidal texture is stabilized by competing instabilities. Specifically, orbital ordering and lone electron pair stereochemical activity compete, giving rise to phase transitions from a nonchiral cubic structure to an incommensurate electric dipole and orbital helix via an intermediate density wave.

中文翻译：

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电偶极子的新兴螺旋结构

偶极子螺旋 在磁性材料中，磁偶极子通常彼此平行或反平行排列。但是，也可能出现更复杂的排序，例如螺旋排序。哈利亚文等人。发现在材料 BiCu0.1Mn6.9O12 中，螺旋顺序可以由电偶极子而不是磁偶极子形成。该材料还具有相关的结构螺旋顺序，对称性分析表明可能可以通过施加的电场进行切换。科学，这个问题 p。四重钙钛矿 BiMn7O12 的 680 光孔掺杂导致异常排序。散装材料中磁偶极子的长程排序产生了广泛的磁性结构，从简单的共线铁磁体和反铁磁体，到通过竞争交换相互作用稳定的复杂磁性螺旋结构。相比之下，介电晶体中的偶极顺序通常限于电偶极子的平行（铁电）和反平行（反铁电）共线排列。在这里，我们报告了通过四重钙钛矿 BiMn7O12 的轻空穴掺杂观察到的电偶极子的不公度螺旋排序。与磁性类似，电偶极螺旋结构通过竞争不稳定性而稳定。具体来说，轨道排序和孤电子对立体化学活性相互竞争，通过中间密度波引起从非手性立方结构到不公度的电偶极子和轨道螺旋的相变。我们报告了通过四重钙钛矿 BiMn7O12 的轻空穴掺杂观察到的电偶极子的不公度螺旋排列。与磁性类似，电偶极螺旋结构通过竞争不稳定性而稳定。具体来说，轨道排序和孤电子对立体化学活性相互竞争，通过中间密度波引起从非手性立方结构到不公度的电偶极子和轨道螺旋的相变。我们报告了通过四重钙钛矿 BiMn7O12 的轻空穴掺杂观察到的电偶极子的不公度螺旋排列。与磁性类似，电偶极螺旋结构通过竞争不稳定性而稳定。具体来说，轨道排序和孤电子对立体化学活性竞争，通过中间密度波引起从非手性立方结构到不公度的电偶极子和轨道螺旋的相变。