Spin-spiral inhomogeneity as the origin of ferroelectric activity in orthorhombic manganites
Spin-spiral inhomogeneity as the origin of ferroelectric activity in orthorhombic manganites
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DOI：
10.1103/physrevb.83.054404
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发表时间：
2010-09
影响因子：
3.7
通讯作者：
I. Solovyev
中科院分区：
文献类型：
--
作者：
I. Solovyev
我们认为，在相对论自旋轨道相互作用下，正交锰氧化物的自旋螺旋态中自旋的均匀分布发生了形变。由此引起的自旋螺旋的不均匀性引起的铁电响应的纯电子的起源在偶数周期性的磁性结构。该机制是通用的，并解释了铁电性的外观在两个倍周期结构的HoMnO 3以及四倍周期结构的TbMnO 3。然而，奇周期磁性结构保持反转对称性，因此不是铁电性的。我们的分析是基于低能量模型来自第一性原理的电子结构计算和贝里相位形式主义的电子极化。
We argue that the homogeneous distribution of spins in the spin-spiral state of orthorhombic manganites is deformed by the relativistic spin-orbit interaction. The thus induced spin-spiral inhomogeneity gives rise to the ferroelectric response of the purely electronic origin in even-periodic magnetic structures. The mechanism is generic and explains the appearance of ferroelectricity in the twofold periodic structure of HoMnO3 as well as the fourfold periodic structure of TbMnO3. Nevertheless, odd-periodic magnetic structures preserve the inversion symmetry and thus are not ferroelectric. Our analysis is based on the low-energy model derived from the first-principles electronic structure calculations and the Berry-phase formalism for the electronic polarization.