Alleviating polarity-conflict at the heterointerfaces of   KTaO$_3$/GdScO$_3$ polar complex-oxides
  We have synthesized and investigated the heterointerfaces of KTaO$_3$ (KTO) and GdScO$_3$ (GSO), which are both polar complex-oxides along the pseudo-cubic [001] direction. Since their layers have the same, conflicting net charges at interfaces, i.e. KO(-1)/ScO$_2$(-1) or TaO$_2$(+1)/GdO(+1), forming the heterointerface of KTO/GSO should be forbidden due to strong Coulomb repulsion, the so-called $\textit{polarity conflict}$. However, we have discovered that atomic reconstruction occurs at the heterointerfaces between KTO thin-films and GSO substrates, which effectively alleviates the polarity conflict without destroying the hetero-epitaxy. Our result demonstrates one of the important ways to create artificial heterostructures from polar complex-oxides. 
J. Thompson, J. Hwang, J. Nichols, J. G. Connell, S. Stemmer, S. S. A.   Seo
cond-mat.mtrl-sci cond-mat.mes-hall