Current Noise in InAs/GaInSb Corbino structures

We report preliminary shot noise measurements in InAs/GaInSb quantum well interfaces. The band structure of these composite quantum wells is inverted, and electron and hole densities are equal at the cross point of the valence and conduction bands. The holes in the strained GaInSb layer couple strongly to the electrons in the InAs layer, opening a gap in the spectrum of the 2d bulk. At low temperatures or when gated into the appropriate regime, bulk transport is greatly suppressed as the hybridized gap is opened. Corbino disk devices consist of concentric rings, meaning no edge conduction is present. Therefore, in these structures, noise measurements examine transport through the bulk and the role played by contacting electrodes. We will compare current noise measurements of samples in the nominal Quantum Spin Hall Insulator state and in the lower-resistance, bulk transport state.