“自旋極化子”的形成源于磁性氧化物中強烈的自旋-電荷-晶格相互作用，它導致載流子局域化，并伴有局域磁化和晶格畸變。CuO是一種有潛力的光陰極材料，其通過自旋極化子跳躍來傳導空穴。自旋極化子在跳躍傳導過程中不僅需要克服強電-聲耦合導致的勢壘，同時還要克服強磁耦合帶來的額外勢壘，因而CuO的電導率很低，這限制了其在光電化學電池陰極及氣體傳感器中的應用。

為克服這一重要限制，來自加州大學圣克魯茲分校和威斯康星大學麥迪遜分校的袁平教授等，提出利用鋰摻雜來提升CuO的電導率?；诘谝辉碛嬎?，他們發現鋰摻雜可以同時降低電-聲耦合及磁耦合導致的勢壘，并且提升載流子濃度。他們進一步制備了Li-CuO電極，與未摻雜CuO電極相比，光電流得到增強。這些結果提示，鋰摻雜CuO有望成為提高磁性氧化物導電性的通用策略。

該文近期發表于npj Computational Materials 4: 61 (2018)，英文標題與摘要如下，點擊左下角“閱讀原文”可以自由獲取論文PDF。

Mechanistic insights of enhanced spin polaron conduction in CuO through atomic doping 

Tyler J. Smart, Allison C. Cardiel, Feng Wu, Kyoung-Shin Choi & Yuan Ping 

The formation of a “spin polaron” stems from strongspin-charge-lattice interactions in magnetic oxides, which leads to alocalization of carriers accompanied by local magnetic polarization and latticedistortion. For example, cupric oxide (CuO), which is a promising photocathodematerial and shares important similarities with high T_csuperconductors,conducts holes through spin polaron hopping with flipped spins at Cu atomswhere a spin polaron has formed. The formation of these spin polarons resultsin an activated hopping conduction process where the carriers must not onlyovercome strong electron?phonon coupling but also strong magnetic coupling.Collectively, these effects cause low carrier conduction in CuO and hinder itsapplications. To overcome this fundamental limitation, we demonstrate fromfirst-principles calculations how doping can improve hopping conduction throughsimultaneous improvement of hole concentration and hopping mobility in magneticoxides such as CuO. Specifically, using Li doping as an example, we show thatLi has a low ionization energy that improves hole concentration, and lowers thehopping barrier through both the electron?phonon and magnetic couplings'reduction that improves hopping mobility. Finally, this improved conductionpredicted by theory is validated through the synthesis of Li-doped CuOelectrodes which show enhanced photocurrent compared to pristine CuOelectrodes. We conclude that doping with nonmagnetic shallow impurities is aneffective strategy to improve hopping conductivities in magnetic oxides.

來源：知社學術圈