The spatially-indirect exciton condensate (SIXC) is an interesting ordered electronic state in　which coherence is spontaneously established between particles localized in separate two-dimensional layers. To date SIXC states have been discovered only in double-quantum-well semiconductor heterojunctions and only in the strong magnetic field quantum Hall regime. I will discuss some properties SIXCs, commenting on their counterflow superfluidity, their collective excitations, and on similarities and differences relative to superconductors, easy-plane ferromagnets and anti-ferromagnets, and the standard model of particle physics. Finally I will discuss the some recent theoretical work SIXC states in bilayers formed from two-dimensional materials, which will hopefully be observed in the future.

【講師紹介】
Allan H. MacDonald 教授は、テキサス大学オースティン校に長年在籍し、凝縮系理論における最先端の研究を指導してこられました。量子ホール効果・スピントロニクス・グラフェンなどの輸送理論を中心として、幅広い研究テーマで顕著な業績をあげられています。