Institute Lorentz for Theoretical Physics, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
Phys Rev Lett. 2010 Jan 8;104(1):017201. doi: 10.1103/PhysRevLett.104.017201. Epub 2010 Jan 4.
The experimental observation of multiferroic behavior in perovskite manganites with a spiral spin structure requires a clarification of the origin of these magnetic states and their relation to ferroelectricity. We show that spin-spiral phases with a diagonal wave vector and also an E-type phase exist for intermediate value of Hund's rule and the Jahn-Teller coupling in the orbitally ordered and insulating state of the standard two-band model Hamiltonian for manganites. Our results support the spin-current mechanism for ferroelectricity and present an alternative view to earlier conclusions where frustrating superexchange couplings were crucial to obtaining spin-spiral states.
实验观察到具有螺旋自旋结构的钙钛矿锰氧化物中的多铁性行为，需要澄清这些磁态的起源及其与铁电性的关系。我们表明，对于标准双带模型哈密顿量中锰氧化物的轨道有序和绝缘态，在 Hund 规则和 Jahn-Teller 耦合的中间值下，存在具有对角波矢的自旋螺旋相和 E 型相。我们的结果支持铁电性的自旋电流机制，并提供了与早期结论不同的观点，其中令人沮丧的超交换耦合对于获得自旋螺旋态至关重要。
