Additionally, experiments using quantum wires (short quantum wires are sometimes referred to as ‘ quantum point contacts ’, (QPCs)) have led to suggestions of Wigner crystallization in 1D systems. In the experiment performed by Hew et al., a 1D channel was formed by confining electrons in both directions transverse to the electron transport, by the band structure of the GaAs / AlGaAs heterojunction and the potential from the QPC. The device design allowed the electron density in the 1D channel to vary relatively independently of the strength of transverse confining potential, thus allowing experiments to be performed in the regime in which Coulomb interactions between electrons dominate the kinetic energy. Conductance through a QPC shows a series of plateaux quantized in units of the conductance quantum, 2 e / h However, this experiment reported a disappearance of the first plateau (resulting in a jump in conductance of 4 e / h), which was attributed to the formation of two parallel rows of electrons. In a strictly 1D system, electrons occupy equidistant points along a line, i.e. a 1D Wigner crystal. As the electron density increases, the Coulomb repulsion becomes large enough to overcome the electrostatic potential confining the 1D Wigner crystal in the transverse direction, leading to a lateral rearrangement of the electrons into a double-row structure. The evidence of a double row observed by Hew et al. may point towards the beginnings of a Wigner crystal in a 1D system.