Formation Of Wigner Crystal Research Articles

Impact of electron-phonon interactions on Wigner crystallization in an electron quantum wire

In this paper, we explore the impact of electron-phonon (e-ph) coupling on the Wigner crystallization occurring due to strong electron-electron (e-e) interactions in a semiconductor-based electron quantum wire. The e-ph coupling is represented by the Fröhlich interaction potential and electron correlations are included within the dynamic version of self-consistent mean-field approximation of Hasegawa and Shimizu. Numerical results are reported for the static structure factor and pair-correlation function for fixed wire width and some selected values of electron number density parameter rs . A strong peak in the static structure factor and pronounced periodic oscillations in pair-correlation function indicate the formation of Wigner crystal in the quantum wire at a critical electron number density rs c . We find that the inclusion of e-ph interactions in addition to the usual e-e interactions significantly enhance rs c , at a fixed wire width.

Effect of the strong electron correlations on the formation of Wigner crystal in n-GaAs/AlGaAs structure: Surface Acoustic Waves studies

The complex high-frequency conductance of high-mobility n-GaAs/AlGaAs heterostructures was determined in magnetic fields 12–18 T using the Surface Acoustic Waves technique. Analysis of frequency and temperature dependences of conductance showed that in the investigated magnetic field range and at low temperatures, T<200 mK, the electron system forms a Wigner crystal deformed due to pinning by disorder. We have also defined an effective melting temperature of the Wigner crystal.

Effects of interedge scattering on the Wigner crystallization in graphene nanoribbons

We investigate the effects of coupling between the two zigzag edges of graphene nanoribbons on the Wigner crystallization of electrons and holes using a combination of tight-binding, mean field Hubbard and many-body configuration interaction methods. We show that the thickness of the nanoribbon plays a crucial role in the formation of Wigner crystal. For ribbon widths smaller than 16 \mbox{\AA}, increased kinetic energy overcomes the long-range Coulomb repulsion and suppresses the Wigner crystallization. For wider ribbons up to 38 \mbox{\AA} wide, strong Wigner localization is observed for even number of electrons, revealing an even-odd effect also found in Coulomb blockade addition spectrum. Interedge correlations are found to be strong enough to allow simultaneous crystallization on both edges, although an applied electric field can decouple the two edges. Finally, we show that Wigner crystallization can also occurs for holes, albeit weaker than for electrons.

Highly Correlated State of π Electrons, Self-organization at Doping, and Superconductivity in Doped Picene

It is shown that superconductivity in doped picene and a number of accompanying effects observed in Mitsuhashi et al. (Nature 464:76 2010) find adequate explanation if we invoke the concept of a highly correlated electron state and the superconductivity model suggested for the high-temperature superconductivity in cuprates that includes formation of a one-dimensional Wigner crystal of electron pairs and its delocalization. It is also shown that the highly correlated state of π electrons in picene results from exchange and Coulomb interactions between the π electrons and leads to formation of a spin-ordered Wigner crystal. Picene doping accompanied by valence electron density redistribution transforms the correlated state of electrons into a highly correlated state of electron pairs manifesting itself in formation of Wigner crystals of electron pairs giving rise to superconductivity of a molecular picene ion. Superconductivity of solid picene includes tunneling of Wigner crystals of pairs through Josephson junctions between molecular picene ions.