Electron-Phonon Scattering in Very High Electric Fields

1997 ◽  
Vol 468 ◽  
Author(s):  
B. K. Ridley
Keyword(s):  
Electric Fields ◽  
Phonon Scattering ◽  
Tight Binding ◽  
Three Dimensional ◽  
Binding Model ◽  
Usual Model ◽  
Scattering Rate ◽  
High Electric Fields ◽  
Very High ◽  
Electron Phonon Scattering

ABSTRACTLarge-bandgap materials can support very high electric fields (>lMV/cm) without breaking down. The possibility then exists for an electron in a conduction band to become quasi-localized in Wannier-Stark states, a possibility that depends on the scattering rate being less than the Bloch oscillation frequency. If this condition is met the scattering rate itself is affected and the description of transport must be changed from the usual model in which the electron is assumed to be virtually free. Here, we examine the feasibility of obtaining this condition in GaN using a simple three-dimensional tight-binding model for the bandstructure and taking the dominant scattering mechanism to be the polar and non-polar interaction with optical phonons and short-wavelength acoustic phonons.

CARBON NANOTUBES AS A PERFECTLY CONDUCTING CYLINDER

2003 ◽  
Vol 13 (03) ◽  
pp. 849-871 ◽  
Author(s):  
TSUNEYA ANDO
Keyword(s):  
Carbon Nanotubes ◽  
Transport Properties ◽  
Phonon Scattering ◽  
Tight Binding ◽  
Point Of View ◽  
Potential Range ◽  
Theoretical Point ◽  
Binding Model ◽  
Long Wavelength ◽  
Electron Phonon Scattering

A brief review is given on electronic and transport properties of carbon nanotubes mainly from a theoretical point of view. The topics include a description of electronic states in a tight-binding model and in an effective-mass or k · p scheme. Transport properties are discussed including absence of backward scattering except for scatterers with a potential range smaller than the lattice constant, its extension to multi-bands cases, and long-wavelength phonons and electron-phonon scattering.

scholarly journals Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Interlayer Coupling ◽  
First Principles Calculation ◽  
Optimization Approach ◽  
Binding Model ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
Topological Quantum ◽  
First Time

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

The effect of electron effective mass mismatch on electron - phonon scattering rate in a quantum well

1997 ◽  
Vol 12 (3) ◽  
pp. 296-299 ◽  
Author(s):  
Zheng Yisong ◽  
Lu Tianquan ◽  
Wang Yiding ◽  
Wu Xuhong ◽  
Zhang Chengxiang ◽  
...  
Keyword(s):  
Quantum Well ◽  
Effective Mass ◽  
Phonon Scattering ◽  
Electron Effective Mass ◽  
Scattering Rate ◽  
Electron Phonon Scattering

Graphene for Magnetoresistive Junctions

2011 ◽  
Vol 1284 ◽  
Author(s):  
J. Inoue ◽  
T. Hiraiwa ◽  
R. Sato ◽  
A. Yamamura ◽  
S. Honda ◽  
...  
Keyword(s):  
Dirac Point ◽  
Electron Tunneling ◽  
Tight Binding ◽  
Metal Electrodes ◽  
Binding Model ◽  
Transition Metal Alloys ◽  
Dependent Change ◽  
Band Mixing ◽  
Junction Structure ◽  
Very High

ABSTRACTInfluence of the linear energy-momentum relationship in graphene on conductance and magnetoresistance (MR) in ferromagnetic metal (FM)/graphene/FM lateral junctions is studied in a numerical simulation formulated using the Kubo formula and recursive Green’s function method in a tight-binding model. It is shown that the contribution of electron tunneling through graphene should be considered in the electronic transport in metal/graphene/metal junctions, and that the Dirac point (DP) is effectively shifted by the band mixing between graphene and metal electrodes. It is shown that MR appears due to spin-dependent shift of DP or spin-dependent change in the electronic states at DPs. It is shown that the MR ratio caused by the latter mechanism can be very high when certain transition metal alloys are used for electrodes. These results do not essentially depend on the shape of the junction structure. However, to obtain high MR ratios, the effects of roughness should be small.

scholarly journals Scalable Majorana vortex modes in iron-based superconductors

2020 ◽  
Vol 6 (9) ◽  
pp. eaay0443 ◽  
Author(s):  
Ching-Kai Chiu ◽  
T. Machida ◽  
Yingyi Huang ◽  
T. Hanaguri ◽  
Fu-Chun Zhang
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Zero Energy ◽  
Binding Model ◽  
Zero Bias ◽  
Iron Based Superconductors ◽  
Iron Based ◽  
Important Indication

The iron-based superconductor FeTexSe1−x is one of the material candidates hosting Majorana vortex modes residing in the vortex cores. It has been observed by recent scanning tunneling spectroscopy measurement that the fraction of vortex cores having zero-bias peaks decreases with increasing magnetic field on the surface of FeTexSe1−x. The hybridization of two Majorana vortex modes cannot simply explain this phenomenon. We construct a three-dimensional tight-binding model simulating the physics of over a hundred Majorana vortex modes in FeTexSe1−x. Our simulation shows that the Majorana hybridization and disordered vortex distribution can explain the decreasing fraction of the zero-bias peaks observed in the experiment; the statistics of the energy peaks off zero energy in our Majorana simulation are in agreement with the experiment. These agreements lead to an important indication of scalable Majorana vortex modes in FeTexSe1−x. Thus, FeTexSe1−x can be one promising platform having scalable Majorana qubits for quantum computing.

Evidence of Channel Mobility Anisotropy on 4H-SiC MOSFETs with Low Interface Trap Density

2019 ◽  
Vol 963 ◽  
pp. 473-478 ◽  
Author(s):  
Maria Cabello ◽  
Victor Soler ◽  
Daniel Haasmann ◽  
Josep Montserrat ◽  
Jose Rebollo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Phonon Scattering ◽  
High Mobility ◽  
Interface State ◽  
Channel Mobility ◽  
Optical Phonon Scattering ◽  
Anisotropy Effect ◽  
State Densities ◽  
High Electric Fields ◽  
Small Anisotropy

In this work, we have evaluated 4° off-axis Si face 4H-SiC MOSFETs channel performance along both the [11-20] (perpendicular to steps) and [1-100] (parallel to steps) orientations, to evidence possible anisotropy on Si-face due to roughness scattering effect. Improved gate oxide treatments, allowing low interface state densities and therefore high mobility values, have been used on both NO and N2O annealed gate oxides. With these high channel mobility samples, a small anisotropy effect (up to 10%) can be observed at high electric fields. The anisotropy can be seen both at room and high temperatures. However, the optical phonon scattering is the dominant effect under these biasing conditions.

Study of Mobility Limiting Mechanisms in (0001) 4H and 6H-SiC MOSFETs

2011 ◽  
Vol 679-680 ◽  
pp. 595-598 ◽  
Author(s):  
Harsh Naik ◽  
T. Paul Chow
Keyword(s):  
Surface Roughness ◽  
Electric Fields ◽  
Phonon Scattering ◽  
Surface Roughness Scattering ◽  
High Electric Fields

To study the mobility limiting mechanisms in (0001) 4H-SiC and 6H-SiC MOSFETs, physics based modeling of the inversion mobility of has been done. Two very different limiting mechanisms have been found for 4H-SiC and 6H-SiC MOSFETs. The mobility in 6H-SiC MOSFETs is limited by phonon scattering while the 4H-SiC MOSFET mobility is limited by Coulombic at low electric fields and surface roughness scattering at high electric fields.

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