Quantum interference of electrons in Nb_{5-\delta}Te_4 single crystals

TL;DR

This study investigates the electronic transport and quantum interference effects in Nb_{5- extdelta}Te_4 single crystals, revealing weak localization, an interplay of quantum effects, and the influence of magnetic impurities on dephasing time.

Contribution

It provides detailed analysis of quantum interference phenomena and dephasing mechanisms in Nb_{5- extdelta}Te_4, highlighting the role of magnetic impurities and electron-phonon interactions.

Findings

Weak localization and antilocalization observed in resistivity.

Dephasing time saturates at low temperatures due to magnetic impurities.

Resistivity shows nonmonotonic behavior with maxima at 2 K and 30 K.

Abstract

The compound $Nb_{5-\delta}Te_4$ ($\delta=0.23$) with quasi-one-dimensional crystal structure undergoes a transition to superconductivity at $T_c$=0.6--0.9 K. Its electronic transport properties in the normal state are studied in the temperature range 1.3--270 K and in magnetic fields up to 11 T. The temperature variation of the resistivity is weak ($<2%$) in the investigated temperature range. Nonmonotonic behavior of the resistivity is observed which is characterized by two local maxima at $T\sim$2 K and $\sim$30 K. The temperature dependence of the resistivity is interpreted as an interplay of weak localization, weak antilocalization, and electron-electron interaction effects in the diffusion and the Cooper channel. The temperature dependence of the dephasing time $\tau_\phi$ extracted from the magnetoresistance data is determined by the electron-phonon interaction. The saturation of $\tau_\phi$ in the low-temperature limit correlates with $T_c$ of the individual crystal and is ascribed to the scattering on magnetic impurities.