Weak Antilocalization Tailor-Made by System Topography in Large Scale Bismuth Antidot Arrays

Abstract

Using a two-carriers model and the Hikami-Larkin-Nagaoka (HLN) theory, we investigate the influence of large area patterning on magnetotransport properties in bismuth thin films with a thickness of 50 nm. The patterned systems have been produced by means of nanospheres lithography complemented by RF-plasma etching leading to highly ordered antidot arrays with the hexagonal symmetry and a variable antidot size. Simultaneous measurements of transverse and longitudinal magnetoresistance in a broad temperature range provided comprehensive data on transport properties and enabled us to extract the values of charge carrier densities and mobilities. Weak antilocalization signatures observed at low temperatures provided information on spin-orbit scattering length ranging from 20 to 30 nm, elastic scattering length of approx. 60 nm, and strong dependence on temperature phase coherence length. We show that in the absence of antidots the charge carrier transport follow 2-dimensional behavior and the dimensionality for phase-coherent processes changes from two to three dimensions at temperature higher than 10 K. For the antidot arrays, however, a decrease of the power law dephasing exponent is observed which is a sign of the 1D-2D crossover caused by the geometry of the system. This results in changes of scattering events probability and phase coherence lengths depending on the antidot diameters, which opens up opportunity to tailor the magnetotransport characteristics.

Manipulating Electrical Properties of Nanopatterned Double-Barrier Schottky Junctions in Ti/TiOx/Fe Systems

“…Additionally, at a low temperature, mesoporous samples have the same value of differential resistance as at the room temperature while nanoporous samples display drop of differential resistance with the size of pores. For the mesoporous sample, the scattering of the electrons at the defects, grain boundaries, and interfaces is the main factor responsible for the sample conductivity since those kind of scattering effects dominates at a low temperature . The origin of the electrical conductivity of nanoporous samples can be assigned to different mechanisms.…”

“…For the mesoporous sample, the scattering of the electrons at the defects, grain boundaries, and interfaces is the main factor responsible for the sample conductivity since those kind of scattering effects dominates at a low temperature. 65 The origin of the electrical conductivity of nanoporous samples can be assigned to different mechanisms. The patterning increases the contact area at the interface between titanium oxide and iron which may lead to stronger iron oxidation than that in the case of mesoporous sample and, consequently, change the probability of electron tunneling through the depletion layer.…”

Electrical Transport and Magnetic Properties of Metal/Metal Oxide/Metal Junctions Based on Anodized Metal Oxides

“…The negative values of seen in Figure 7 are the result of normalization procedure, and no negative differential resistance was obtained for our samples. The positive value of magnetoresistance is a result of Lorentz force acting on electrons leading to a parabolic shape of known as ordinary magnetoresistance of metals [ 57 , 58 ]. At low temperature, the negative anisotropic is strong in the TAF sample and dominates for the whole range of magnetic fields, while, for the FAF sample, it is weaker and turns into positive parabolic dependence after reaching magnetic saturation.…”

Magnetotransport Properties of Semi-Metallic Bismuth Thin Films for Flexible Sensor Applications

“…Coatings 2021, 11, x FOR PEER REVIEW 2 of 10 structures and their magnetotransport properties is expanding fast [18][19][20][21][22]. Bi films can be fabricated by various techniques such as liquid-based exfoliation [23,24], molecular beam epitaxy [25], and acid intercalated exfoliation [26].…”

“…Thin layers and nanostructures of bismuth offer also a very high magnetoresistance, reaching even 380,000% at low temperatures [17]. These properties make bismuth a good candidate for the use in sensors, and the literature devoted to the fabrication of low dimensional Bi structures and their magnetotransport properties is expanding fast [18][19][20][21][22]. Bi films can be fabricated by various techniques such as liquid-based exfoliation [23,24], molecular beam epitaxy [25], and acid intercalated exfoliation [26].…”