Phonon drag

About: Phonon drag is a research topic. Over the lifetime, 762 publications have been published within this topic receiving 11219 citations.

Thermal conductance and thermopower of an individual single-wall carbon nanotube.

Abstract: We have observed experimentally that the thermal conductance of a 2.76-μm-long individual suspended single-wall carbon nanotube (SWCNT) was very close to the calculated ballistic thermal conductance of a 1-nm-diameter SWCNT without showing signatures of phonon−phonon Umklapp scattering for temperatures between 110 and 300 K. Although the observed thermopower of the SWCNT can be attributed to a linear diffusion contribution and a constant phonon drag effect, there could be an additional contact effect.

Thermoelectric Power of Metals

Abstract: 1 Introduction- 11 Seebeck, Peltier, and Thomson Effects- 12 Transport Coefficients and Onsager Relations- 2 Survey of the Theory of Electronic Conduction in Metals- 21 Electrons in Metals- 21a Free Electron Gas- 21b Energy Bands- 22 Transport Properties- 23 Relaxation Time Anisotropy for Spherical Fermi Surfaces- 24 Thermopower: Isotropic Relaxation Time Approximation- 25 Thermopower: Real Metals- 25a Alkali and Noble Metals- 25b Polyvalent Metals- 26 Phonon Drag- 27 Thermopower of Alloys- 27a Diffusion Thermopower- 27b Phonon Drag- 3 Techniques in Thermoelectric Measurements- 31 Introduction- 32 Seebeck Effect- 33 Peltier Effect- 34 Thomson Effect: The Absolute Thermopower of Lead- 35 Measurement of Unconventional Thermoelectric Coefficients- 36 Measurement of Temperature and of Small Voltages- 36a Temperature Measurement- 36b Voltage Measurement- 37 Superconducting Devices- 37a Superconducting Modulators- 37b Weak Link and Josephson Junction Devices-SQUIDS and Slugs- 37b1 SQUIDS- 37b2 Slugs- 4 Phonon Drag- 41 Introduction and General Relations- 42 Sg at High Temperatures- 43 Sg at Low Temperatures- 43a Low-Temperature Phonon Drag in the Alkali Metals- 43b Low-Temperature Phonon Drag in Other Metals- 44 Anisotropy of Relaxation Times and Phonon-Drag Thermopower- 45 Sg at Intermediate Temperatures- 46 Sg of Alloys- 47 Phonon Drag or Phony Phonon Drag?- 47a Pure Metals- 47b Dilute Alloys- 47c Evidence for "Phony Phonon Drag"- 47d Effects of Higher-Order Scattering Processes- 5 The Thermoelectric Power of Transition Metals- 51 Special Problems in Transition Metals- 51a s- and d-Conduction- 51b Electron-Electron Collisions- 51c Magnetic Effects: Collective Electrons and Isolated Spins- 51d Magnetic Effects: Magnons and Paramagnons- 51e Magnetic Effects: Spin Mixing- 51f Magnetic Effects: The Curie and Neel Temperatures- 52 The Diffusion Thermopower of Transition Metals- 52a Phonons and Impurities- 52b Electron-Electron Scattering- 52c Magnons and Paramagnons- 52d Two-Current Conduction and Spin Mixing- 52e Curie Point Anomalies- 53 The Phonon-Drag Thermopower of Transition Metals- 54 Magnon Drag- 55 Transition Elements: Summary of Experimental Results- 55a The Magnetic Elements: Cr, Mn, Fe, Co, and Ni- 55b The "Thermocouple" Elements: Fe, Pt, Re, and W- 56 Commercial Thermocouples- 56a Copper vs Constantan (Type T)- 56b Iron vs Constantan (Type J)- 56c Chromel vs Constantan (Type E)- 56d Chromel vs Alumel (Type K)- 56e Tungsten vs Tungsten-Rhenium (Types G* and C*)- 56f Platinum vs Platinum-Rhodium (Types R, S, and B)- 6 Dilute Magnetic Alloys- 61 Introduction- 62 The Virtual Bound State- 62a Electronic Properties for VBS Systems- 62b Survey of Experimental Results for VBS Systems- 63 Kondo Alloys- 63a Theory of the Kondo Effect- 63b Thermoelectric Power of Kondo Alloys- 64 Spin-Fluctuation Models- 65 Closing Comment- 7 Effects of Pressure and Magnetic Field on the Thermoelectric Power- 71 Pressure Dependence- 71a Introduction- 71b Practical Thermocouples- 71c Fundamental Studies- 71c1 Diffusion Thermopower- 71c2 Phonon-Drag Thermopower- 72 Magnetic Field Dependence- 72a Introduction- 72b Practical Thermocouples- 72c Fundamental Studies- 72d Landau Quantization Effects- References- Author Index

Transport properties of silicon

Abstract: Electrical conductivity, thermal conductivity, and thermoelectric power of single-crystalline silicon are investigated at temperatures between 2 and 300 K. From the measured data we calculate the mean free path of electrons and phonons and separate diffusion part and phonon-drag part of the thermoelectric power. Using a new method, we evaluate the mean free path of those phonons which are responsible for the phonon drag effect.

Length scale and time scale effects on the plastic flow of fcc metals

Abstract: We examine size scale and strain rate effects on single-crystal face-centered cubic (fcc) metals. To study yield and work hardening, we perform simple shear molecular dynamics simulations using the embedded atom method (EAM) on single-crystal nickel ranging from 100 atoms to 100 million atoms and at strain rates ranging from 107 to 1012 s−1. We compare our atomistic simulation results with experimental data obtained from interfacial force microscopy (IFM), nano-indentation, micro-indentation and small-scale torsion. The data are found to scale with a geometric length scale parameter defined by the ratio of volume to surface area of the samples. The atomistic simulations reveal that dislocations nucleating at free surfaces are critical to causing micro-yield and macro-yield in pristine material. The increase of flow stress at increasing strain rates results from phonon drag, and a simple model is developed to demonstrate this effect. Another important aspect of this study reveals that plasticity as reflected by the global averaged stress–strain behavior is characterized by four different length scales: (1) below 104 atoms, (2) between 104 and 106 atoms (2 μm), (3) between 2 μm and 300 μm, and (4) above 300 μm.

Atomistic simulations of dislocation mobility in Al, Ni and Al/Mg alloys

Abstract: Dislocation velocities and mobilities are studied using molecular dynamics simulations for edge and screw dislocations in pure aluminium and nickel, and edge dislocations in Al-2.5%Mg and Al-5.0%Mg random substitutional alloys using EAM potentials. In the pure materials, the velocities of all dislocations are close to linear with the ratio of (applied stress)/(temperature) at low velocities consistent with phonon drag models, and quantitative agreement with the experiment is obtained for the mobility in Al. At higher velocities, different behaviour is observed. The edge dislocation velocity remains dependent solely on (applied stress)/(temperature) up to approximately 1.0 MPa K(-1), and approaches a plateau velocity that is lower than the smallest 'forbidden' speed predicted by continuum models. In contrast, above a velocity around half of the smallest continuum wave speed, the screw dislocation damping has a contribution dependent solely on stress with a functional form close to that predicted by a radiation damping model of Eshelby. At the highest applied stresses, there are several regimes of nearly constant (transonic) velocity separated by velocity gaps in the vicinity of forbidden velocities; various modes of dislocation disintegration and destabilization were also encountered in this regime. In the alloy systems, there is a temperature- and concentration-dependent pinning regime where the velocity drops sharply below the pure metal velocity. Above the pinning regime but at moderate stresses, the velocity is again linear in (applied stress)/(temperature) but with a lower mobility than in the pure metal.