Experimental Progress towards Probing the Ground State of an Electron-Hole Bilayer by Low-Temperature Transport

Figure 9

Hole drag resistivity versus temperature shown for 𝑛=𝑝=9,10,14,17×10¹⁰ cm⁻², down to 300 mK. Electron drag is only shown for 𝑛=𝑝=9×10¹⁰ cm⁻² for clarity. (Device: B138/C4-1-10 nm Barrier). The drag voltage was measured in two ways, by sending current through the electrons and measuring the open-circuit voltage across the holes (𝜌_drag,h=𝑉_h/𝐼_e) or by sending current through the holes and measuring the voltage across the electrons (𝜌_drag,e=𝑉_e/𝐼_h). As long as the current is low enough so that the system is in the linear response regime, thermodynamic arguments [54] predict that 𝜌_drag,e=𝜌_drag,h.