My understanding is that for weak localization the presence of weak disorder leads to some electron paths interfering destructively since there is an equal probability for it to take one complete "circle" in one direction to taking the same path in the opposite direction so the phases cancel, resulting in fewer electrons diffusing all the way through the material and hence we would measure an increase in resistivity. The last bit is the part I don't get, I would have thought that if the two paths interfere destructively then surely the resistivity would increase? What does the spin-orbit coupling change, since that seems to be the only difference between antilocalization and localization which seem to result in two opposite effects on the resistivity. Because of this, the two paths any loop interfere destructively which leads to a lower net resistivity. The spin of the carrier rotates as it goes around a self-intersecting path, and the direction of this rotation is opposite for the two directions about the loop. In a system with spin-orbit coupling the spin of a carrier is coupled to its momentum. (a) The weak antilocalization phase coherence length (AL) and the weak localization phase coherence length (L) as functions of for weak (so 10000nm). D.On Wikipedia (pretty much the only place I can find an explanation of what weak anti-localization actually is) it is explained as: Agreement between β values thus obtained becomes full if effects of the strong electron–electron interaction are taken into account in the weak antilocalization model within a simplified approach by renormalizing the effective mass of the electron. The difference between these coupling constants is apparently due to the strong electron–electron interaction. A close spin–orbit coupling constant β = 7.6 meV Å has been independently determined from the modification of the single-particle g‑factor measured using electron paramagnetic resonance in the quantum Hall effect regime in the same sample. The approximation of the experimental data gives the Dresselhaus spin–orbit coupling constant β = 10.1 meV Å. The corresponding corrections to the conductivity have been described well within the diffusion model proposed in. To summarize, the weak antilocalization effect in a narrow AlAs quantum well containing a two-dimensional electron system with a large effective mass at low temperatures has been studied for the first time. 2019), which assumes infinite phase coherence length (l) and a zero spinorbit. The chosen m* value is in satisfactory agreement with the masses obtained in from the analysis of the behavior of Shubnikov–de Haas oscillations in similar structures at different temperatures. The present study develops a general framework for weak antilocalization (WAL) in a three-dimensional. We emphasize that the quality of the approximation of experimental data with both the band and renormalized masses is the same. The low-temperature values of the two-dimensional electron density and mobility were \(n = 7.7 \times \) = 35 ps is shown in Fig. Ohmic contacts to the two-dimensional channel were formed by the deposition and subsequent annealing of indium into the contact regions. The sample had the form of a standard 200-μm-wide Hall bar with drain/source and six potentiometric contacts (see Fig. 1a). Thus, the study of the weak antilocalization effect in strongly correlated electron system hosted in the AlAs quantum well is exceptionally important and, in particular, can result in refining existing theories and creation of new ones.Įxperiments were performed on a 4-nm AlAs/AlGaAs quantum well grown in the direction using molecular beam epitaxy. We emphasize that most theories used to describe the discussed quantum corrections are single-particle. The key parameters or length scales to determine the strength of weak localization or anti-localization are phase coherence length and SOI induced spin. The combination of these properties makes such material systems very promising for the study of fundamental collective phenomena associated with the spin degree of freedom of the electron. Furthermore, as shown in, narrow AlAs quantum wells are also characterized by a quite strong spin–orbit coupling. In two-dimensional electron systems with a comparable effective mass, a number of striking multiparticle phenomena are observed, including Wigner crystallization, Stoner ferromagnetic transition in the quantum Hall effect regime, and condensation of spin waves. The large effective mass ensures a low kinetic energy compared to the characteristic Coulomb energy and is responsible for a significant role of the strong electron–electron interaction. The effective mass of the electron in this structure is m b = 0.25 m 0. In this work, we detect for the first time the weak antilocalization effect in a narrow AlAs quantum well containing a two-dimensional electron system.
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