Non‐Poissonian Shot Noise in Tunneling Semiconductor Heterostructures

We have found experimentally that when the motion of electrons is correlated in multibarrier tunneling semiconductor heterostructures, the current spectral density of the shot noise is non‐Poissonian. That the value is smaller or larger than 2eI depends on whether the correlation is negative or positive. Although existing models can qualitatively explain our results, they cannot account quantitatively for some of the findings, suggesting an incomplete understanding of noise in multi‐barrier structures.