Low-temperature magnetoresistance of functionalized multiwall carbon nanotubes

Abstract

Temperature and magnetic field dependencies of resistance for functionalized multiwall carbon nanotubes (MWCNTs) have been studied. The measurements were carried out in the temperature range T = 4.2–200 K. It is shown that in magnetic fields up to B = 9 T, the conductivity behavior for the functionalized MWCNTs sample can be described in terms of charge carriers weak localization and interaction phenomena. We show that the contribution to the functionalized MWCNTs conductivity due to the weak localization effect exceeds the quantum correction due to the effect of the charge carriers interaction for all the temperatures and in the entire range of the applied magnetic fields except for the magnetic fields above B = 6.5 T at T = 5 K. Within the terms of the specified models, we estimate the value of the Fermi energy and determine the explicit form of the temperature dependence of the phase relaxation time for the wave function. We show that for the functionalized MWCNTs sample, the phase relaxation time for the wave function has a less pronounced temperature dependence, and its Fermi energy is more shifted to the valence band compared to non-functionalized MWCNTs. The charge carriers’ interaction constant at different temperatures can also be estimated from our experiments.

The Impact of Topological States on the Thermoelectric Performance of p- and n-Type Sb2Te3/Bi2Se3-Multiwalled Carbon Nanotubes Heterostructured Networks

“…Phase coherence length l φ and prefactor α determined using the Hikami-Larkin-Nagaoka theory for p-type and n-type Bi2Se3-MWCNT networks for the 2-10 K temperature range. [28][29][30], and WAL, originating from Bi 2 Se 3 nanostructures. It was shown previously that the WL and WAL may coexist in the quantum diffusion regime in systems where the mean free path of the charge carrier due to elastic scattering is much shorter than the sample size, but the phase coherence length l φ due to inelastic scattering is comparable with the sample size.…”

“…In recent years, topological insulator nanostructures have been found to exhibit magnetoresistance properties characterized by weak anti-localization (WAL) effects at temperatures below 30 K and low magnetic fields, which originate from the surface states of these materials [23][24][25][26][27]. In turn, the magnetoresistance of CNTs at low temperatures and low magnetic fields reveals the presence of weak localization (WL) effects [28][29][30]. The observation of WL and WAL effects in TI-CNT heterostructures, originating from the interface or interplay of the heterostructure components, may shed light on the dominating charge transfer processes occurring in these systems at different temperatures.…”