论文标题
由极化物的电荷和掺杂味的缺陷引起的轨道旋转
Orbital Rotations induced by Charges of Polarons and Defects in Doped Vanadates
论文作者
论文摘要
我们探索掺杂孔和缺陷的竞争，这导致了钒酸盐钙化物中轨道秩序的损失。在诸如la $ _ {1- {\ sf x}} $ ca $ _ {\，\ sf x} $ ca $ _3 $ spin和轨道订单之类的化合物中带电的CA $^{2+} $缺陷和$ E $ - $ E $交互控制Mott GAP内缺陷状态的出现。掺杂孔的库仑场的四极组件诱导退化轨道的各向异性轨道旋转。这些旋转改变了自旋轨道极化子云，并与缺陷引起的轨道旋转竞争。两种机制都会导致轨道的混合，并在$ C $ -Type磁相中引起动能的不对称性。我们发现，轨道顺序随掺杂的逐渐下降，但是，杂质的特征是其起源并不主要是在电荷载体中，而是在掺杂离子的指控引起的轨道旋转的偏外耦合中。
We explore the competiton of doped holes and defects that leads to the loss of orbital order in vanadate perovskites. In compounds such as La$_{1-{\sf x}}$Ca$_{\,\sf x}$VO$_3$ spin and orbital order result from super-exchange interactions described by an extended three-orbital degenerate Hubbard-Hund model for the vanadium $t_{2g}$ electrons. Long-range Coulomb potentials of charged Ca$^{2+}$ defects and $e$-$e$ interactions control the emergence of defect states inside the Mott gap. The quadrupolar components of the Coulomb fields of doped holes induce anisotropic orbital rotations of degenerate orbitals. These rotations modify the spin-orbital polaron clouds and compete with orbital rotations induced by defects. Both mechanisms lead to a mixing of orbitals, and cause the suppression of the asymmetry of kinetic energy in the $C$-type magnetic phase. We find that the gradual decline of orbital order with doping, a characteristic feature of the vanadates, however, has its origin not predominantly in the charge carriers, but in the off-diagonal couplings of orbital rotations induced by the charges of the doped ions.
