Kumar Sanjeev, Kampf Arno P, Majumdar Pinaki
Institute of Physics, Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany.
Phys Rev Lett. 2006 Oct 27;97(17):176403. doi: 10.1103/PhysRevLett.97.176403. Epub 2006 Oct 24.
The ground state of a double-exchange model for orbitally degenerate e(g) electrons with Jahn-Teller lattice coupling and weak disorder is found to be spatially inhomogeneous near half filling. Using a real-space Monte Carlo method we show that doping the half-filled orbitally ordered insulator leads to the appearance of hole-rich disordered regions in an orbitally ordered environment. The doping driven orbital order to disorder transition is accompanied by the emergence of metallic behavior. We present results on transport and optical properties along with spatial patterns for lattice distortions and charge densities, providing a basis for an overall understanding of the low-doping phase diagram of La1 - xCaxMnO3.
具有 Jahn-Teller 晶格耦合和弱无序的轨道简并 e(g) 电子的双交换模型的基态在半填充附近被发现是空间不均匀的。使用实空间蒙特卡罗方法，我们表明对半填充的轨道有序绝缘体进行掺杂会导致在轨道有序环境中出现富空穴的无序区域。掺杂驱动的轨道有序到无序转变伴随着金属行为的出现。我们给出了输运和光学性质的结果，以及晶格畸变和电荷密度的空间模式，为全面理解 La1 - xCaxMnO3 的低掺杂相图提供了基础。
