论文标题
la $ _ {0.7} $ ca $ _ {0.3} $ mno $ _3 $在极端拉伸菌株下的属性
Properties of La$_{0.7}$Ca$_{0.3}$MnO$_3$ Under Extreme Tensile Strain
论文作者
论文摘要
具有同时活跃的自旋，电荷，轨道和晶格自由度的锰矿的复杂相图继续提供惊喜。在最近的开创性实验中，在柔性聚合物层上沉积的钙钛矿锰的膜LA $ _ {0.7} $ ca $ _ {0.3} $ mno $ _3 $（lcmo）的膜最高为8 \％[s.〜s。 Hong {\ it等人}，Science {\ bf 368}，71（2020）]，比刚性底物引起的常规应变所实现的要多得多。通过增加这种菌株，据报道金属 - 绝缘体的跃迁。在这里，我们使用两轨道双交换模型的蒙特卡洛模拟重现了实验的结果，包括jahn-teller畸变，孔密度$ x = 1/3 $。提出了带有不同温度和Jahn Teller耦合$λ$的全相图。当减少带宽$ w $移动电子的$ W $时，因此，当有效的Jahn Teller耦合$λ/W $增加时，在我们的模拟中发现了金属 - 绝缘体的过渡，在具有均匀的电荷电荷分布的铁磁金属状态和带有射频电荷的二氧磁性电荷的二磁性金属状态之间，将其转移到了其垂体上。在富含孔的对角线之间，发生交错的轨道顺序。我们还报告了电阻率和磁化测量以及自旋相关性和电荷结构因子。我们的总体结论与Hong {\ it等人}的最新实验和密度功能理论结果一致，我们使用T. hotta {\ it等人的能量优化技术证实了条纹铁磁秩序的基础状态预测。莱特牧师。 {\ bf 86}，4922（2001）。从理论上预测的一个状态之一的实验观察表明，如果lcmo膜具有该孔掺杂，则可以在其他孔密度下（例如$ x = 1/4 $）实现对角条纹。
The complex phase diagram of manganites with simultaneously active spin, charge, orbital, and lattice degrees of freedom continues providing surprises. In a recent groundbreaking experiment, membranes of the perovskite manganite La$_{0.7}$Ca$_{0.3}$MnO$_3$ (LCMO) deposited on a flexible polymer layer were strained up to 8\% [S.~S. Hong {\it et al.}, Science {\bf 368}, 71 (2020)], much more than achieved by regular strain induced by a rigid substrate. By increasing this strain a metal-insulator transition was reported. Here we reproduce the results of the experiments using Monte Carlo simulations of the two-orbital double-exchange model including Jahn-Teller distortions, at hole density $x=1/3$. The full phase diagram with varying temperature and Jahn-Teller coupling $λ$ is presented. When the bandwidth $W$ of mobile electrons is reduced, thus when the effective Jahn-Teller coupling $λ/W$ is increased, a metal-insulator transition is found in our simulations, between a ferromagnetic metallic state with uniform charge distribution and an insulator with diagonal charge stripes that retains its ferromagnetic character. In between the hole-rich diagonals, staggered orbital order occurs. We also report resistivity and magnetization measurements alongside with spin correlations and charge structure factors. Our overall conclusions are in agreement with the recent experimental and density functional theory results by Hong {\it et al.}, and we confirm much earlier ground state predictions of striped ferromagnetic order using energy optimization techniques by T. Hotta {\it et al.}, Phys. Rev. Lett. {\bf 86}, 4922 (2001). The experimental observation of one of the states predicted by theory suggests that diagonal stripes could be achieved at other hole densities as well, such as $x=1/4$, if LCMO membranes with that hole doping were subject to similar strains.
