Electrical Resistivity Of Metals Research Articles

Strong electron-phonon interaction induced significant reduction in lattice thermal conductivities for single-layer MoS2 and PtSSe

Electron-phonon interaction (EPI) has been widely suited in electrical transport properties, such as electrical resistivity in metals and electronic mobility in semiconductors. Nevertheless, its critical impact on lattice thermal transport has just been revealed in recent years, particularly for two-dimensional materials. Here, we emphatically report the carrier concentration dependent EPI effect on the lattice thermal conductivities for single-layer transitional metal dichalcogenide MoS2 and PtSSe by first-principles calculations. In particular, when the EPI effect is considered, the lattice thermal conductivities at 300 K are significantly reduced by as much as 39% (42%) and 78% (55%) at 6.5 × 1013 cm−2 for hole (electron) doping of MoS2 and PtSSe, respectively. This abnormal suppression effect on thermal conductivity due to strong EPI for hole doping of PtSSe can be profoundly understood by its strong electron-phonon coupling strength and characteristic band structure. The former can be further rationalized by the breaking of the horizontal symmetry in PtSSe. Our work presents a deep insight into EPI effect on lattice thermal conductivity and provides a new perspective to search for strong EPI induced low thermal conductivity materials.

Topological Singularity Induced Chiral Kohn Anomaly in a Weyl Semimetal.

The electron-phonon interaction (EPI) is instrumental in a wide variety of phenomena in solid-state physics, such as electrical resistivity in metals, carrier mobility, optical transition, and polaron effects in semiconductors, lifetime of hot carriers, transition temperature in BCS superconductors, and even spin relaxation in diamond nitrogen-vacancy centers for quantum information processing. However, due to the weak EPI strength, most phenomena have focused on electronic properties rather than on phonon properties. One prominent exception is the Kohn anomaly, where phonon softening can emerge when the phonon wave vector nests the Fermi surface of metals. Here we report a new class of Kohn anomaly in a topological Weyl semimetal (WSM), predicted by field-theoretical calculations, and experimentally observed through inelastic x-ray and neutron scattering on WSM tantalum phosphide. Compared to the conventional Kohn anomaly, the Fermi surface in a WSM exhibits multiple topological singularities of Weyl nodes, leading to a distinct nesting condition with chiral selection, a power-law divergence, and non-negligible dynamical effects. Our work brings the concept of the Kohn anomaly into WSMs and sheds light on elucidating the EPI mechanism in emergent topological materials.

Influence of temperature and pressure on the electrical resistivity of gold and copper up to 1350 K and 100 GPa

In this work, we have presented a new approach investigating the influence of temperature and pressure on the electrical resistivity of metals. In the framework of the statistical moment method, high temperatures up to 1350 K and high pressure up to 100 GPa electrical resistivity of Au and Cu are calculated. The equation of state, the Gruneisen parameter, and the Debye temperature of these metals are also discussed. The results show a good agreement with other theoretical calculations and the experimental data.

A Noncontact Method for Measuring the Specific Electrical Resistance of Metals in the High-Temperature Region

An extremely simple noncontact method for measuring the resistivity of metals at high temperatures is proposed. The essence of this method is to measure the electromotive force induced by a high-frequency electromagnetic field in two circular circuits of different diameters, which are placed coaxially in the middle of a cylindrical sample. The results of measuring the resistivity of molybdenum in the range of 1170–2070 K using contact and noncontact methods coincide within ±1%, thus making it possible to recommend the proposed method as efficient and preferable, especially in the high-temperature region. A technique for processing the experimental results is described and recommendations on the optimal geometries of the circuits and sample are given to improve the accuracy of measurements.

A Hardware-Software Complex for Measuring the Electrical Resistance of Metals and Alloys at High Temperatures

The hardware-software complex of an experimental device intended for measuring the electrical resistance of metallic conductors at high temperatures is considered. Designs of individual elements by means of which stable operation and high precision of the results of measurements may be achieved are proposed. The device is tested using ARMCO iron.

Measuring the electric resistance of metals and alloys at high temperatures by a hardware-and-software system

Measuring the electric resistance of metals and alloys at high temperatures by a hardware-and-software system

Dependences of valence electronic structure on magnetic moment and electrical resistivity of metals

Conventionally, the energy band theory is used to explain the magnetic and electrical transport properties of metals. However, so far, there has been no quantitative explanation of the relations between the average magnetic moment per atom and the resistivity for Fe, nor Ni, nor Co metals. In this paper, a new itinerant electron model for magnetic metal is proposed on the basis of electron distribution theory at the energy level. 1) In the process of free atoms forming the metal solid, most of the 4s electrons of Fe, Ni and Co enter into the 3d orbits subjected to the Pauli repulsive force, and the remaining 4s electrons form free electrons. 2) Since the average number of 3d electrons is not an integer, a part of atoms have one 3d electron more than the other atoms. These excess 3d electrons have a certain probability to itinerate between the 3d orbits of the adjacent atoms as itinerant electrons; and the other 3d electrons are local electrons. 3) The transition probability of itinerant electrons is very low, thus the contribution to metal resistivity from itinerant electrons is far lower than that from free electrons. Resistivity of metal decreases with increasing the number of free electrons. Therefore, using the observed values of average atomic magnetic moments, 2.22, 0.62 and 1.72 B, the average numbers of free electrons in Fe, Ni and Co can be calculated to be 0.22, 0.62 and 0.72, respectively. This is the reason why the electrical resistivities of Fe, Ni and Co (8.6, 6.14 and 5.57 -cm) decease successively. In addition, according to this model, the average number of 3d electrons per atom in Ni metal is 9.38. This indicates that 38% of atoms in Ni metal have ten 3d electrons, forming a full 3d sub-shell, as in Cu or Zn atoms. The 3d electrons in these atoms are difficult to itinerate or exchange. This may be the reason why the Curie temperature of Ni metal (631 K) is far lower than those of Fe and Co metals (1043 and 1404 K). On the basis of the energy band theory, the numbers of 3d electrons in Fe, Ni and Co metals are 7.4, 9.4 and 8.3, which are close to our results (7.78, 9.38 and 8.28), respectively. This indicates that our model is consistent with the energy band theory. Compared with the complex energy band theory, a simple and effective method on investigating valence electron structures through the experimental average magnetic moments per atom in a metal is presented based on our model. Therefore, the new itinerant electron model may be a new clue to understanding the electronic structure of metals and alloys.

Research Progress on Effect of Length Scale on Electrical Resistivity of Metals

With the development of micro/nano-technologies, microstructural scales or geometrical dimensions of metal conductors in the micro/nano-devices are becoming shrunk from macroscopic scale to micron scale, submicron scale and even nanometer scale, leading to the fact that the electrical resistivity of metal conductors at room temperature tends to exhibit evident size effects. Recent studies on the electrical resistivity of metal conductors at different length scales were reviewed in this paper, focusing on the effects of the geometrical scales of microscalematerials and of the scale of microstructures and defects in the materials as well as the relevant theoretical models. Finally the developing tendency of the investigations on the electrical resistivity of metal conductors and the service reliability of the microscale metals in the future are also addressed.

All-Metallic High-Performance Field Effect Transistor Based on Telescoping Carbon Nanotubes: An ab Initio Study

It has been well established that the electrical resistance of metal is insensitive to gate voltage and unsuitable for making field effect transistors. However, we find that telescoping pristine do...

Design and application of a device based on electromagnetic induction principle for electrical resistivity qualitative measurement of liquid and solid metals

A non-contact measuring device for electrical resistivity has been designed, which is based on electromagnetic induction principle. Using the device, the electrical resistivity of metals can be monitored during transition from liquid to solid state, which shows that the device is suitable for analysing the structure transition of metals and alloys during the cooling process.The design principle and construction of the device are detailedly described in this paper. The change of electrical resistivity of pure Zn and pure Sb, and hypereutectic Zn-70wt.%Sb alloy during cooling was measured by the device. The experiment results show that the device preforms well.

The correlation between electrical resistivity of metals and thermal deformation

A simple expression is given, which defines the unique correlation between phonon electrical resistance and the product of true coefficient of volumetric thermal expansion into temperature from ∼0 K to melting temperature. This expression is derived as a result of correlation analysis of experimental data on electrical resistivity and coefficient of thermal expansion of non-transition metals. This expression is validated within the phenomenological theory of condensed media.

Wide band negative magnetic permeability materials (NMPM) with composite metalsemiconductor structures based on the Drude model, and applications to negative-refractive index (NIM)

Composite structures based on metal open rings and thin wires are well established, for obtaining efficient negative index materials (NIM), acting as metamaterials in the long wavelength regime. The main losses are due both to metal absorption and to the inner electric resistance of metals; to overcome this latter loss we propose a new metal-semiconductor structure dimensioned by direct synthesis method, which offers an almost perfect Drude-like effective magnetic permeability. The choice of particular semiconductor components allows to get a negative resistance for the current induced by the electromagnetic field, which cancels that of the metal but puts a limit to the spectral response of the metamaterial. We consider some parasite effects, such as bianisotropy and incorrect values of structural parameters, to see limitations and features of this new NIM technology.

A new algorithm for accurate evaluation of the generalized Bloch–Gruneisen function and its applications to MgB2 superconductor

The objective of this Letter is to provide an efficient and reliable analytical procedure for the generalized Bloch–Gruneisen function with the Debye temperatures for the wide temperature range using the binomial expansion theorems. As will be seen, the present formulation yields compact closed-form expressions which enable the ready calculation of Bloch–Gruneisen function for integer and noninteger values of parameter m. The proposed procedure guarantees the reliable application of the contribution of electron–photon interaction to the electrical resistivity of metals. Finally, the algorithm is used to simulate the variation of the resistivity and thermal conductivity against temperature sintered polycrystalline MgB2. Furthermore, the comparison of the method with numerical calculations demonstrates the applicability and accuracy of the method.

Saturation of electrical resistivity in metals at large temperatures.

We present a microscopic model for systems showing resistivity saturation. An essentially exact quantum Monte Carlo calculation demonstrates that the model describes saturation. We give a simple explanation for saturation, using charge conservation and considering the limit where thermally excited phonons have destroyed the periodicity. Crucial model features are phonons coupling to the hopping matrix elements and a unit cell with several atoms. We demonstrate the difference to a model of alkali-doped C60 with coupling to the level positions, for which there is no saturation.

Effect of plastic deformation on the electrical resistivity of metals

Results from measurements of the electrical resistivity of copper and aluminum conductors under the action of a plane shock wave, and also analysis of the relationship between the electrical resistivity and the hydrostatic pressure and of the theoretical temperature dependence of the electrical resistivity, has made it possible to elucidate the role of defect formation due to the plastic deformation of the metal and to determine its contribution to the increase in electrical resisitivity of the metal. It has been established that the concentration of defects depends on the pressure gradient in a plane shock wave.

Electron scattering rate in epitaxial YBa2Cu3O7 superconducting films.

This work determines the electron scattering rate in the a-b plane of epitaxial ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ films using two techniques. Infrared spectroscopy yields the scattering rate at temperatures of 10, 78, and 300 K by fitting reflectance data using thin-film optics and a model for the free-carrier conductivity. The scattering rate is also obtained using kinetic theory and an extrapolation of normal-state electrical resistivity data to superconducting temperatures based on the Bloch theory for the phonon-limited electrical resistivity of metals. The scattering rates determined using both techniques are in agreement and show that the electron mean free path in the a-b plane of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ superconducting films is three to four times the coherence length. Hence ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ is pure but not in the extreme pure limit. An average defect interaction range of 4 nm is obtained using the defect density resulting from flux-pinning considerations.

Relationship of the electrical resistance of metals to their strength in heating

A review is given of literature sources on the use of data on the electrical conductivity of metals in studying their strength. It is shown that a correlation relationship between strength and electrical resistance is possible for relatively pure metals.

A novel theory of radiation damage at high doses

Abstract The deviations of radiation damage (in the case of metals usually monitored by the residual electrical resistivity) from proportionality to the irradiation dose have so far been analysed almost exclusively in terms of extensions of models originally developed for small doses. The present theory considers the opposite limit, i. e. the quasi-saturated state. It is argued that at high doses the Lück-Sizmann effect may result in a self-organization of clusters of vacancies and self-intersititials, forming a heterogeneous froth. Possible structures of this froth and its effect on the electrical resistivity of metals are discussed. The model is shown to account for the dependence of the “saturation resistivity” on the nature of the irradiation as well as for several other hitherto poorly explained observations. Among them are the electrical-resistivity variation induced by high-dose irradiation with heavy ions, the amorphization of certain alloys by high-dose electron irradiation, and the occurrence of ordered arrays of stacking-fault tetrahedra after in-situ irradiations in high-voltage electron microscopes.

Studying the coefficient of thermal conductivity for liquid metals

We discuss a method for an experimental study of the coefficient of thermal conductivity, specific heat capacity, and the specific electrical resistance of metals in the solid and liquid states, as well as the data that we have obtained with respect to the indicated properties of Bi, In, Cd, and Pb.

Calculation of electrical resistivity produced by dislocations in various metals

An elementary discussion is presented of how the atomic disorder near a dislocation line can produce enough large-angle scattering to account for the measured values of electrical resistivity in metals. The anisotropy of conduction electron scattering over the Fermi surface is deduced from analysis of the model. The values of specific dislocation resistivity calculated in different metals generally agree well with measured values. There is some comment on the broad trend of resistivity values in different metals produced by dislocations, which is similar to the trend of phonon-produced resistivity. A critique of certain other theoretical models is also presented.