![]() The extremely large magnetoresistance and high mobility of topological insulators have great technological value and can be exploited in magnetoelectric sensors and memory devices. At high charge-carrier concentrations, there is a greater number of conduction channels and a decrease in the phase coherence length compared to low charge-carrier concentrations. With weak anti-localization because the spin is related to the momentum which depends on the path then the 'forward' and 'backward' paths interfere. on the weak-localization effect, the destruction of the phase coherence of the wave. The physical parameters characterizing the WAL effects are calculated using the Hikami-Larkin-Nagaoka formula. With weak localization, the back scattering is enhanced due to the constructive interference of the paths around the closed loop. This chapter discusses the weak-localization contribution to the. Meanwhile, universal conductance fluctuations have temperature and gate voltage dependence that is similar to that of the phase coherence length. The observations of an extremely large nonsaturating magnetoresistance and ultrahigh mobility in the samples with lower carrier density further support the presence of surface states. Notably, the temperature-dependent phase coherence length extracted from weak antilocalization agrees with strong electron-electron scattering in the sample. We present low-temperature magnetoresistance measurements on lithographically defined bismuth wires. WAL due to topological surface states shows no dependence on the nature (electrons or holes) of the bulk charge carriers. At high charge-carrier density the WAL curves scale with neither the applied field nor its normal component, implying a mixture of bulk and surface conduction. From ts to these data using the Hikami-Larkin-Nagaoka model, the phase coherence length of each device is extracted, as well as the spin diffusion length of the p-type device. At low charge-carrier density the WAL curves scale with the normal component of the magnetic field, demonstrating the dominance of topological surface states in magnetoconductivity. This work offers insights for understanding quantum electrical transport phenomena and their underlying physics, particularly when multiple WAL length scales are competing.Weak antilocalization (WAL) effects in Bi 2 Te 3 single crystals have been investigated at high and low bulk charge-carrier concentrations. The present theory describes both low-T and high-T regions successfully, which is impossible in the previous approximate approach. Accordingly, the hallmark features of weak antilocalization (WAL) in ρ xx(B ) ? and ρ xy(B ) ? are gradually suppressed across the crossover with increasing T. Because of the different T dependence, a crossover occurs from the l SO-dominant low-T to the l ϕ-dominant high-T regions. Information on phase-coherence can be obtained by analyzing transport phenomena such as weak (anti)localization and universal conductance fluctuations in structures of the according length scale 24. In contrast, the l SO shows negligible T dependence. The l ϕ has a power-law T dependence at high T and saturates at low T. By sharing the same origin, the difference arises due to the significance of the electron spin, expressed by the spin-orbit scattering length. The present framework not only explains the main features of the experimental data but also enables one to estimate l ϕ and l SO at different temperatures. Weak antilocalization and localization, as electron interference effects, both require a sufficiently large phase-coherence length relative to the system geometry. is much shorter than the sample size and phase coherence length, phase coherence of. The data were analyzed using the most representative theories on the weak antilocalization (WAL) correction to magnetoconductivity. 8.5.4.3 Near Zero Field: Weak Antilocalization As the magnetic field. Weak localization is a physical effect which occurs in disordered electronic systems at very low temperatures. Weak localization is due primarily to self-intersecting scattering paths. ![]() Based on the new approach, the ρ xx(B ) ? and ρ xy(B ) ? of the Dirac semimetal Bi 0.97Sb 0.03 was analyzed over a wide T range from 1.7 to 300 K. We have investigated the weak antilocalization effect in a high-density two-dimensional electron gas (2DEG) in an AlGaN/GaN heterostructure. There are many possible scattering paths in a disordered system. (Phys Rev B 100:125162, 2019), which assumes infinite phase coherence length (l ϕ) and a zero spin-orbit scattering length (l SO), the present framework is more general, covering high T and the intermediate spin-orbit coupling strength. Compared to the previous approach Vu et al. The present study develops a general framework for weak antilocalization (WAL) in a three-dimensional (3D) system, which can be applied for a consistent description of longitudinal resistivity ρ xx(B ) ? and Hall resistivity ρ xy(B ) ? over a wide temperature (T) range.
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