Excitonic Correlation in Coulomb-Coupled Electron-Hole Double Layers

In a spatially separated electron-hole system such as InAs-GaSb-based quantum wells, a number of phases and phase transitions are theoretically predicted to occur, including quantum spin Hall insulator, excitonic insulator, and broken symmetry states, such as nematic phase or Chern insulator. Motivated by this exciting prospect and with the advant of high quality semiconductor material grown by MBE technique we explore low temperature electrical transport properties in InAs/GaInSb bilayers with a AlSb middle barrier. The devices were made with flip-chip technique to facilitate dual-gate control of carrier densities. Preliminary results concerning excitonic correlation in this system will be presented.