Magic Angle Effects and AMRO as Dimensional Crossovers

TL;DR

This paper explains how interference effects in low-dimensional conductors cause dimensional crossovers at Magic Angles, leading to sharp resistivity minima that account for observed AMRO phenomena.

Contribution

It demonstrates that wave function dimensionality changes at Magic Angles due to interference effects, providing a new explanation for AMRO features in low-dimensional conductors.

Findings

Dimensional crossovers occur at Magic Angles due to interference effects.

Sharp minima in resistivity Rzz are observed at Magic Angles.

The theory explains qualitative features of AMRO in specific low-dimensional conductors.

Abstract

It is shown that interference effects between velocity and density of states, which occur as electrons move along open orbits in the extended Brillouin zone, result in a change of wave functions dimensionality at Magic Angle (MA) directions of a magnetic field. In a particular, we demonstrate that these 1D -> 2D dimensional crossovers result in the appearance of sharp minima in a resistivity component Rzz, perpendicular to conducting layers, which explains the main qualitative features of MA and Angular Magneto-Resistance Oscillations (AMRO) phenomena observed in low-dimensional conductors (TMTSF)2X, (DMET-TSeF)2X, and a-(BEDT-TTF)2MHg(SCN)4.