论文标题
LACOO的热电运输中的著名电子孔不对称$ _3 $
Prominent electron-hole asymmetry in thermoelectric transport of LaCoO$_3$
论文作者
论文摘要
我们已经测量了电阻率和电子掺杂的钙钛矿钴矿物laco $ _ {1-y} $ te $ _y $ o $ o $ _3 $。与金属掺杂的系统（例如金属掺杂的系统）相反CO $^{3+} $站点在能量上被抑制。我们发现，尽管具有电子掺杂，但热电厂显示出$ y = 0.05 $的较大的正值，与掺杂掺杂的孔接近零的情况下，明显不同。在热电器中看到的这种突出的电子孔不对称起源于双极传导，该传导由少量的移动孔和主要的固定电子组成，表明自旋状态阻断对热电运输的影响。
We have measured the electrical resistivity and the thermopower of the electron-doped perovskite cobaltites LaCo$_{1-y}$Te$_y$O$_3$. In contrast to the hole-doped systems such as metallic ferromagnets La$_{1-x}M_x$CoO$_3$ ($M$ = Ca, Sr, Ba), the electron-doped samples show an insulating behavior even in a heavily doped range due to a spin-state blockade mechanism that an electron hopping from high-spin Co$^{2+}$ to low-spin Co$^{3+}$ site is energetically suppressed. We find that, despite the electron doping, the thermopower shows relatively large positive values above $y=0.05$, strikingly distinct from the hole-doped case where it comes close to zero with doping. This prominent electron-hole asymmetry seen in the thermopower originates from a bipolar conduction which consists of a slight amount of mobile holes and the main immobile electrons, demonstrating an impact of spin-state blockade on thermoelectric transport.
