Correlated interface electron gas in infinite-layer nickelate versus cuprate films on SrTiO3 (001)
Correlated interface electron gas in infinite-layer nickelate versus cuprate films on SrTiO3 (001)
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DOI：
10.1103/physrevresearch.3.013261
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发表时间：
2021-03-19
影响因子：
4.2
通讯作者：
Pentcheva, Rossitza
中科院分区：
文献类型：
--
作者：
Geisler, Benjamin;Pentcheva, Rossitza
基于包含库仑排斥项的第一性原理计算，我们确定了ANiO（2）/SrTiO 3（001）（A = Pr，La）和ACuO（2）/SrTiO 3（001）（A = Ca，Sr）的电子重构趋势。所有情况的共同点是SrTiO 3（001）中准二维电子气（q2 DEG）的出现，尽管镍酸盐与铜酸盐与非极性SrTiO 3（001）衬底的界面处的较高极性失配（3+/0与2+/0）导致q2 DEG载流子密度增强。模拟结果表明，一个显着的依赖关系的界面Ti 3d（xy）带弯曲的稀土金属离子的镍酸盐薄膜，是20-30%的PrNiO 2和NdNiO 2比LaNiO 2。相反的预期，从正式的极性不匹配，在薄膜中的静电掺杂是两倍强的铜酸盐镍酸盐。我们表明，自掺杂稀土金属5d状态的耗尽增强了镍酸盐和铜酸盐费米表面在膜几何形状的相似性，反映了在Ni和Cu 3d（x2-y2）轨道中的单个空穴。最后，我们表明，生长在极性NdGaO 3（001）衬底上的NdNiO 2薄膜具有同时抑制q2 DEG形成以及Nd 5d自掺杂。
Based on first-principles calculations including a Coulomb repulsion term, we identify trends in the electronic reconstruction of ANiO(2)/SrTiO3 (001) (A = Pr, La) and ACuO(2)/SrTiO3 (001) (A = Ca, Sr). Common to all cases is the emergence of a quasi-two-dimensional electron gas (q2DEG) in SrTiO3 (001), albeit the higher polarity mismatch at the interface of nickelates versus cuprates to the nonpolar SrTiO3 (001) substrate (3+/0 versus 2+/0) results in an enhanced q2DEG carrier density. The simulations reveal a significant dependence of the interfacial Ti 3d(xy) band bending on the rare-earth-metal ion in the nickelate films, being 20-30% larger for PrNiO2 and NdNiO2 than for LaNiO2. Contrary to expectations from the formal polarity mismatch, the electrostatic doping in the films is twice as strong in cuprates as in nickelates. We demonstrate that the depletion of the self-doping rare-earth-metal 5d states enhances the similarity of nickelate and cuprate Fermi surfaces in film geometry, reflecting a single hole in the Ni and Cu 3d(x2-y2) orbitals. Finally, we show that NdNiO2 films grown on a polar NdGaO3 (001) substrate feature a simultaneous suppression of q2DEG formation as well as Nd 5d self-doping.