  Breaking of inversion symmetry leads to nonlinear and nonreciprocal electron
transport, in which the voltage response does not invert with the reversal of
the current direction. Many systems have incorporated inversion symmetry
breaking into their band or crystal structures. In this work, we demonstrate
that a conventional two-dimensional electron gas (2DEG) system with a back gate
shows non-reciprocal behavior (with voltage proportional to current squared) in
the quantum Hall regime, which depends on the out-of-plane magnetic field and
contact configuration. The inversion symmetry is broken due to the presence of
the back gate and magnetic field, and our phenomenological model provides a
qualitative explanation of the experimental data. Our results suggest a
universal mechanism that gives rise to non-reciprocal behavior in gated
samples.
