Fig. 3: Chirality-dependent tunnelling current response.
From: Spin polarization detection via chirality-induced tunnelling currents in indium selenide
a, Magnetic field dependence of the tunnelling current (ITC) measured at VG = −6 V and 250 μW of laser power for the 5L device. The signal is shown for different excitation chiralities (linearly polarized (LP), and left- and right-handed circularly polarized). The current observed at a positive (negative) magnetic field for σ– (σ+) is equivalent to the linearly polarized response. This allows us to electrically detect the chirality of light at a given magnetic field in an originally achiral system. The asymmetry is caused by the Zeeman splitting of the hBN bands, which now presents a different energy barrier height for different spin populations in the InSe layer, thereby favouring one population when the respective energy barrier is lowered. b, Tunnelling differential conductance (GTDC) can be extracted for different InSe layer numbers and multiple devices, showing that the observed signal is independent of the InSe layer number. Two examples are shown: 3L (blue) and 5L (red). Interestingly, the tunnelling differential conductance increases linearly with the magnetic field, and a total value of around 5% is obtained at ±5 T and 150 μW. The errors plotted are the standard deviations of the conductance values within the specified intervals.
