Metallic conduction and large electron-phonon-impurity interference effect in single TiSi nanowires

Abstract

We report on the first electrical characterizations of single-crystalline TiSi nanowires (NWs) synthesized by chemical vapor deposition reactions. By utilizing the focused-ion-beam-induced deposition technique, we have delicately made four-probe contacts onto individual NWs. The NW resistivities have been measured between 2 and 300 K, which reveal overall metallic conduction with small residual resistivity ratios in the NWs. Surprisingly, we find that the effect due to the interference processes between the elastic electron scattering and the electron-phonon scattering largely dominates over the usual Boltzmann transport even at room temperature. Such prominent electron-phonon-impurity interference effect is ascribed to the presence of large amounts of disorder and high Debye temperatures in TiSi NWs.

Estimation of temperature coefficient of resistance for microfabricated platinum thermometers in thermal conductivity measurements of one-dimensional nanostructures

“…The ratio of R el-ph to R EPI is 1.2, 5.6 and 11.8 at 35 K, 150 K and 360 K, respectively. Our fitting result agrees with the measurements on thin gold films [14], but is opposite to the results on TiSi nanowires [17]. For 10-30 nm thick gold films [14], ρ EPI is larger than ρ el-ph only below ∼20 K. However, the EPI effect is still dominant at room temperature in TiSi nanowires [17], which was attributed to the large Debye temperature and high levels of disorder in the TiSi samples.…”

“…Thermal strain and impurities in a thermometer could cause the resistivity to deviate from the BG formula [10,14,16,17]. The effect of the thermal strain on the resistivity can be considered by adding a term bT to the BG formula, where b is a free parameter [10].…”

“…Impurities in metal can enhance the interference between electron-phonon scattering and electron-impurity scattering (EPI), which causes deviation of ρ(T ) from the BG formula. This deviation can be expressed as [14,17]…”

Electron-phonon coupling in copper intercalated Bi$_{2}$Se$_{3}$

“…Although, the quantum and EE corrections to the conductivity in Bi 2 Se 3 have been extensively studied [1][2][3][4][5][6][7] and the strength of the electron-phonon coupling has been determined e.g. by using ARPES [8] and surface phonons [9], very little is known about the effect of the interference between EP and electron-impurity scattering on electrical transport, which has been of great interest in disordered metallic conductors [10] and nanowires [11]. In disordered materials, for example intercalated crystals, the EP and electron-impurity interference processes result in a T 2 contribution to conductivity [12].…”

Electron–phonon coupling in copper intercalated Bi$$_{2}$$Se$$_{3}$$

“…Although, the quantum and EE corrections to the conductivity in Bi Se have been extensively studied 1 – 7 and the strength of the electron–phonon coupling has been determined e.g. by using ARPES 8 and surface phonons 9 , very little is known about the effect of the interference between EP and electron-impurity scattering on electrical transport, which has been of great interest in disordered metallic conductors 10 and nanowires 11 .…”