scholarly journals Precision measurement of electron-electron scattering in GaAs/AlGaAs using transverse magnetic focusing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adbhut Gupta ◽  
J. J. Heremans ◽  
Gitansh Kataria ◽  
Mani Chandra ◽  
S. Fallahi ◽  
...  
Keyword(s):  
Scattering Length ◽  
Ballistic Transport ◽  
High Mobility ◽  
Transverse Magnetic ◽  
Electron Systems ◽  
Solid State Physics ◽  
Temperature Dependent ◽  
Magnetic Focusing ◽  
Collective Phenomenon ◽  
Predominant Effect

AbstractElectron-electron (e-e) interactions assume a cardinal role in solid-state physics. Quantifying the e-e scattering length is hence critical. In this paper we show that the mesoscopic phenomenon of transverse magnetic focusing (TMF) in two-dimensional electron systems forms a precise and sensitive technique to measure this length scale. Conversely we quantitatively demonstrate that e-e scattering is the predominant effect limiting TMF amplitudes in high-mobility materials. Using high-resolution kinetic simulations, we show that the TMF amplitude at a maximum decays exponentially as a function of the e-e scattering length, which leads to a ready approach to extract this length from the measured TMF amplitudes. The approach is applied to measure the temperature-dependent e-e scattering length in high-mobility GaAs/AlGaAs heterostructures. The simulations further reveal current vortices that accompany the cyclotron orbits - a collective phenomenon counterintuitive to the ballistic transport underlying a TMF setting.

Temperature Dependent Raman Scattering in CsTiOAsO4 Single Crystal

1995 ◽  
Vol 398 ◽  
Author(s):  
A.R. Guo ◽  
C.-S. Tu ◽  
Ruiwu Tao ◽  
R.S. Katiyar ◽  
Ruyan Guo ◽  
...  
Keyword(s):  
Soft Mode ◽  
Low Frequency ◽  
High Mobility ◽  
Vibrational Modes ◽  
Frequency Range ◽  
Temperature Dependent ◽  
Higher Symmetry ◽  
Phonon Spectra ◽  
Symmetry Structure ◽  
Increasing Temperature

ABSTRACTThe longitudinal (LO) and transverse (TO) A1 vibrational modes have been measured between 30-1200 cm−1 as a function of temperature (30–1240 K) for CsTiOAsO4 (CTA). The frequencies for all corresponding Raman components shifted to lower frequencies on increasing the temperature, however, there is no typical soft-mode like behavior observed in the measured frequency range. The relative intensities of the low frequency bands increase dramatically with increasing temperature due to high mobility of Cs+ ion. A higher symmetry structure taking place above 940K has been confirmed by changes in the phonon spectra.

Comparative Performance Analysis of Nanowire and Nanotube Field Effect Transistors

2021 ◽  
pp. 54-70
Author(s):  
Raj Kumar ◽  
Shashi Bala ◽  
Arvind Kumar
Keyword(s):  
Performance Analysis ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Ballistic Transport ◽  
High Mobility ◽  
Short Channel Effects ◽  
Short Channel ◽  
Comparative Performance ◽  
Channel Effects ◽  
And Performance

To have enhanced drive current and diminish short channel effects, planer MOS transistors have migrated from single-gate devices to three-dimensional multi-gate MOSFETs. The gate-all-around nanowire field-effect transistor (GAA NWFET) and nanotube or double gate-all-around field-effect transistors (DGGA-NTFET) have been proposed to deal with short channel effects and performance relates issues. Nanowire and nanotube-based field-effect transistors can be considered as leading candidates for nanoscale devices due to their superior electrostatic controllability, and ballistic transport properties. In this work, the performance of GAA NWFETs and DGAA-NT FETs will be analyzed and compared. III-V semiconductor materials as a channel will also be employed due to their high mobility over silicon. Performance analysis of junctionless nanowire and nanotube FETs will also be compared and presented.

scholarly journals Ballistic transport in periodically modulated MgZnO/ZnO two-dimensional electron systems

2019 ◽  
Vol 115 (15) ◽  
pp. 153101 ◽  
Author(s):  
K. Tanaka ◽  
J. Falson ◽  
Y. Kozuka ◽  
M. Uchida ◽  
D. Maryenko ◽  
...  
Keyword(s):  
Ballistic Transport ◽  
Two Dimensional ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Two Dimensional Electron Systems

A ROOM TEMPERATURE BALLISTIC DEFLECTION TRANSISTOR FOR HIGH PERFORMANCE APPLICATIONS

2009 ◽  
Vol 19 (01) ◽  
pp. 23-31 ◽  
Author(s):  
QUENTIN DIDUCK ◽  
HIROSHI IRIE ◽  
MARTIN MARGALA
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Ballistic Transport ◽  
High Mobility ◽  
Mean Free Path ◽  
Material System ◽  
Novel Device ◽  
Ballistic Electron ◽  
Ballistic Deflection Transistor ◽  
Channel Separation

The Ballistic Deflection Transistor (BDT) is a novel device that is based upon an electron steering and a ballistic deflection effect. Composed of an InGaAs - InAlAs heterostructure on an InP substrate, this material system provides a large mean free path and high mobility to support ballistic transport at room temperature. The planar nature of the device enables a two step lithography process, as well, implies a very low capacitance design. This transistor is unique in that no doping junction or barrier structure is employed. Rather, the transistor utilizes a two-dimensional electron gas (2DEG) to achieve ballistic electron transport in a gated microstructure, combined with asymmetric geometrical deflection. Motivated by reduced transit times, the structure can be operated such that current never stops flowing, but rather is only directed toward one of two output drain terminals. The BDT is unique in that it possesses both a positive and negative transconductance region. Experimental measurements have indicated that the transconductance of the device increases with applied drain-source voltage. DC measurements of prototype devices have verified small signal voltage gains of over 150, with transconductance values from 45 to 130 mS/mm depending upon geometry and bias. Gate-channel separation is currently 80nm, and allows for higher transconductance through scaling. The six terminal device enables a normally differential mode of operation, and provides two drain outputs. These outputs, depending on gate bias, are either complementary or non-complementary. This facilitates a wide variety of circuit design techniques. Given the ultralow capacitive design, initial estimates of ft, for the device fabricated with a 430nm gate width, are over a THz.

Temperature-dependent ballistic transport in a channel with length below the scattering-limited mean free path

2012 ◽  
Vol 111 (5) ◽  
pp. 054301 ◽  
Author(s):  
Vijay K. Arora ◽  
Mastura Shafinaz Zainal Abidin ◽  
Michael L. P. Tan ◽  
Munawar A. Riyadi
Keyword(s):  
Free Path ◽  
Ballistic Transport ◽  
Mean Free Path ◽  
Temperature Dependent

scholarly journals Scaling approach to tight-binding transport in realistic graphene devices: The case of transverse magnetic focusing

2016 ◽  
Vol 94 (11) ◽  
Author(s):  
M. Beconcini ◽  
S. Valentini ◽  
R. Krishna Kumar ◽  
G. H. Auton ◽  
A. K. Geim ◽  
...  
Keyword(s):  
Tight Binding ◽  
Transverse Magnetic ◽  
Magnetic Focusing ◽  
Graphene Devices

scholarly journals Spin Dynamics in High-Mobility Two-Dimensional Electron Systems

2008 ◽  
pp. 143-155 ◽  
Author(s):  
Tobias Korn ◽  
Dominik Stich ◽  
Robert Schulz ◽  
Dieter Schuh ◽  
Werner Wegscheider ◽  
...  
Keyword(s):  
Spin Dynamics ◽  
High Mobility ◽  
Two Dimensional ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Two Dimensional Electron Systems

scholarly journals High Temperature Superconductors Through the Van Hove Singularity

2021 ◽  
Author(s):  
◽  
Keryn Anne Williams
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
High Temperature Superconductors ◽  
Bcs Theory ◽  
Magnetic Data ◽  
Metallic State ◽  
Solid State Physics ◽  
Temperature Dependent ◽  
Doped Semiconductors ◽  
Exotic Physics

<p>The antibonding VHS of the high temperature superconductor Bi-2212 appears in the extreme overdoped regime, a part of the cuprate phase diagram little studied to date. Observation of this VHS motivated taking a fresh look at the cuprates using fundamentals of electronics as the foundation for understanding the physics involved in the superconductivity of these materials. In the study of the high temperature superconductors it appears important questions have been overlooked, notably the possible contribution of the gapped state and whether these materials are better considered as doped semiconductors rather than as 'poor' metals. We also find the question of the contribution of oxygen, a substance with a strong magnetic signature, to data of the oxygen-doped cuprates has been neglected. Comparison with non-oxygen doping is supportive of the view the oxygen dopant contributes noticeably to magnetic data. Through magnetic susceptibility measurements the antibonding VHS location, predicted by use of Fermi liquid theory, is well confirmed in polycrystals of the lead-doped cuprate Bi-2212. It was found that the peak in the DOS at the VHS produces no corresponding local peak in the critical temperature versus doping. Instead, the VHS appears associated with the disappearance of the superconductivity, rather than with the maximum critical temperature. We find the metal-insulator transition plays an important role. There are two of these in the cuprates, a horizontal doping dependent one and a vertical temperature dependent one. They affect each other. Noting the consequences of doping an insulator until a metallic state is reached enables a connection to be made between doping and pressure. Three requirements are identified for superconductivity to occur: 1. screening 2. pairing 3. charge mobility Each requirement may be separately satisfied in a manner whereby each can vary differently as a function of the same variable. The superconductivity of the cuprates is found to arise out of an underlying non-metallic state. As such, BCS theory, being formulated to explain superconductivity arising from metallic conduction, cannot be directly applicable. However, although HTS materials are a rich repository of both novel and familiar solid state physics, evidence does not appear to support the notion that superconductivity in the cuprates is caused by "exotic" physics. We also find cause for optimism regarding the development of new or improved superconducting materials.</p>

scholarly journals OSCILLATORY AND VANISHING RESISTANCE STATES IN MICROWAVE IRRADIATED 2D ELECTRON SYSTEMS

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3465-3472 ◽  
Author(s):  
R. R. DU ◽  
M. A. ZUDOV ◽  
C. L. YANG ◽  
Z. Q. YUAN ◽  
L. N. PFEIFFER ◽  
...  
Keyword(s):  
High Frequency ◽  
High Mobility ◽  
Electron System ◽  
Two Dimensional ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Dimensional Electron System ◽  
Zero Resistance ◽  
The Subject ◽  
Shubnikov De Haas Oscillations

Giant-amplitude oscillations in dc magnetoresistance of a high-mobility two-dimensional electron system can be induced by millimeterwave irradiations, leading to zero-resistance states at the oscillation minima. Following a brief overview of the now well-known phenomenon, this paper reports on aspects of more recent experiments on the subject. These are: new zero-resistance states associated with multi-photon processes; suppression of Shubnikov-de Haas oscillations by high-frequency microwaves; and microwave photoconductivity of a high-mobility two-dimensional hole system.

Sign in / Sign up

Export Citation Format

Share Document