News and Such

 New publication 26th July, 2020Schematics of a wrap round gate silicon nanowire field effect transistor of length 55 nm cut away to expose the channel region. The oxide thickness is 0.8 nm and the channel width is 2.2 nm. The channel length (gate length) is 15 nm, the source and drain extensions are 20 nm. The work function of the metal gate is 4.5 V. The projected image shows a typical non equillibrium Green function (NEGF) computed local density of states (LDOS) for the device assuming a drain bias of 0.6V and a gate bias at 0.6 V. The location of the first 1D sub band edge is shown along the central nanowire x axis as a function of energy and position (dashed white line); it mimics the self consistent potential along the same axis. In the projected image, the vertical energy scale is from -0.6 eV to 0.23 eV.

Quantum transport in a silicon nanowire FET transistor:
hot electrons and local power dissipation
ANTONIO MARTINEZ and JOHN R BARKER
Materials, 13 (15),3326-3367 (2020)
published on-line at: https://doi.org/10.3390/ma13153326

Open access: available on line

Covid-19 outbreak Modelling (March 2020)

The data from the World Health organisation provides some help in understanding the spread of the disease. There are simple ways to analyse these data in an empirical spirit:

Logistic function and complementary Fermi function for simple modelling of the COVID-19 pandemic: tutorial notes, John R Barker, download here: logistic function COVID19

But there are words of caution in taking this too far:

Why your COVD-19 exponential fits are wrong: words of caution and a lesson from catastrophe theory, John R Barker: download here Words of caution

Research Page    describes COVID-19 notes and research

Public Lectures:

12th February, 2019
The Exploration of Space: John R Barker
University of Glasgow Retired Staff Association, Glasgow

14th March, 2018
The Exploration of Space: the Austerity Years: John R Barker
Royal Philosophical Society of Glasgow,
John Anderson Building, Strathclyde University, 7.30 p.m.

Recent Conference Papers

International Workshop on Computational Nanotechnology
5-9 June 2017, Low Wood Hotel, Windermere, UK

Image charge models for accurate construction of the electrostatic self-energy of 3D layered nanostructure devices
John R Barker and Antonio Martinez

Dissipative NEGF methodology to treat short range Coulomb
interaction: Current through a 1D Nanostructure
Antonio Martinez, John R Barker and Riccardo Di Pietro

Dave Ferry & John Barker, Windermere, 2017

Euro-TMCS II: Theory, Modelling and Computational Methods for Semiconductors, Tyndall National Institute at University College, Cork, Republic of Ireland , 7-9 th December, 2016

Impact of short range Coulomb repulsion on the current through a 1D nanostructure
Antonio Martinez, John R Barker, Riccardo Di Pietro

UK Semiconductors Conference, University of Sheffield Hallam, July 2016

Current enhancement due to short-range Coulomb interaction in Quasi-open Systems
A. Martinez , J.R. Barker, R. Pietro

International Workshop on Computational Electronics,
West Lafayette, Indiana, 2-4 September, 2015

Impact of Discrete Dopants in Ultrascale FinFETs and the Effect of XC on Dopant Clustering
Antonio Martinez, Raul Valin and John R Barker

UK Semiconductors Conference, University of Sheffield Hallam, July 2015

Impact of local exchange-correlation in a FinFet device with dopant clustering
Antonio Martinez, Raul Valin and John R Barker

Euro-TMCS I: Theory, Modelling and Computational Methods for Semiconductors, University of Granada, Spain , 28-30 January, 2015

1. Effect of exchange-correlation in a FinFet device with dopant clustering
Antonio Martinez, Raul Valin and John R Barker

2. Impact of Fixed Oxide Charge on Ultra-scaled FinFets
Raul Valin, Antonio Martinez, Manuel Aldegnde and John R Barker

ESSDERC 2014
44th European Solid-State Device Research Conference
September 22-26, 2014 – Venice, Italy

Impact of Discrete Dopants on an Ultra-scaled
FinFET Using Quantum Transport Simulations
R. Valin, A. Martinez, and M. Aldegunde, J. R. Barker

Semiconductors UK 2014 July 9-10, Sheffield

Phonon scattering in ultra-scaled tri-gate FET
A. Martinez, R, Valin, M. Aldegunde, A. Price and J.R. Barker

International Workshop on Computational Electronics
Paris, France 3-6 th June 2014

1. Impact of Lateral Doping Profiles on Ultra-scaled Trigate FinFETs
R. Valin, M. Aldegunde, A. Martinez and J. R. Barker

2. TiN Work Function Variability on Ultra-scaled FinFETs using a NEGF formalism
R. Valin, A. García-Rivera, M. Aldegunde, A. Martinez, and J. R. Barker

3. Remote soft-optical phonon scattering in Si nanowire FETs
J. R. Barker and A. Martinez

Theory, Modelling and Computational Methods for Semiconductors IV
University of Salford, UK 23-24 January, 2014

1. Causal self-energies for NEGF modelling of quantum nanowires
John Barker, Antonio Martinez, Manuel Aldegunde and Raul Valin

2. Impact of different electron-phonon scattering models on the electron
transport in a quantum wire
Anna Price, Antonio Martinez, Raul Valin and John Barker

UK Semiconductors Conference, Sheffield, July, 2013

“Causal self-energies for quantum nanowires”
John R. Barker and Antonio Martinez

International Workshop on Computational Electronics,

Nara, Japan, June, 2013

Short Course (Invited)

“The Non-Equilibrium Green Function Approach to Quantum Transport in Nano-Structures”              John R Barker

Download: Lecture Material

A few photos

A few photos

Contributed Papers

“Impact of Dielectric Induced Dynamical Many-Body Correlation Effects on the Transfer Characteristic of Si Nanowire Transistor”
A. Martinez, J.R. Barker, and M. Aldegunde

“Dependence of Matthiessen’s Rule on Complex Phonon Self-Energies: A NEGF Study”
M. Aldegunde, R. Valin, A. Martinez, and J.R. Barker

“Impact of Scaling on the Variability in Multigate Transistors”
M. Aldegunde, A. Martinez, and J.R. Barker

Materials Research Society Spring Meeting San Francisco April (2013)

“Self-energy Models for Scattering in Semiconductor Nanoscale Devices: Causality Considerations and the Spectral Sum Rule”
John  R  Barker, and Antonio  Martinez.

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Newsflash: observation of Surreal Bohmian trajectories 2016

Newsflash: breakthrough on observation of photon trajectories

Glasgow Science Festival Talk

International Workshop on Progress in Non-Equilibrium Green Functions IV

Nanovisions exhibition

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Announcement of 2020 Nobel Prize in Physics

The Nobel Prize in Physics 2020 was divided, one half awarded to Roger Penrose “for the discovery that black hole formation is a robust prediction of the general theory of relativity”, the other half jointly to Reinhard Genzel and Andrea Ghez “for the discovery of a supermassive compact object at the centre of our galaxy.”

Professor Roger Penrose lLecturing in Edinburgh 9th March, 2013

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Announcement of 2016 Nobel Prizes

The Nobel Prize in Chemistry 2016
Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa
“for the design and synthesis of molecular machines”

The Nobel Prize in Physics 2016
David J. Thouless, F. Duncan M. Haldane and J. Michael Kosterlitz
“for theoretical discoveries of topological phase transitions and topological phases of matter”

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Announcement of 2013 Nobel Prize in Physics

8th October 2013

Congratulations to Professor Peter Higgs and Professor Francois Englert for the Nobel Prize in Physics 2013.

“For the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the Atlas and CMS experiments at Cern’s Large Hadron Collider”

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Outreach: some talks in 2012

6.30 p.m., November 19th, 2012: Royal Observatory at Greenwich
Flamsteed Astronomical Society
Remote Exploration of rocky planets: craters to smart dust
Prof John Barker

10.30 a.m.,November 27th, 2012  Jordanhill Parish Church
Kelvin Probus Club, Glasgow
A question of Cosmology
Prof John Barker

2 p.m., 6th December, 2012
University of Swansea: College of  Engineering
Green functions and Causality: exploring Electron Transport in Nanowires
Prof John Barker
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Higgs Announcement

4th July, 2012

CERN reports that the Large Hadron Collider has indeed found evidence for a new particle consistent with the Higgs boson predicted by the Standard Model.

I obtained this photo of Peter Higgs as a screen capture from the live video feed of the News Conference at CERN.

Peter Higgs at CERN 04-07-2012

We have to wait to find out if the new particle is a scalar or pseudo scalar or whatever. Exciting times!

Note added in October: At the annual statutory meeting of the Royal Society of Edinburgh on Monday 1 October, Professor Higgs FRS FRSE was awarded a specially-commissioned medal in recognition of his outstanding work that led to the recent announcement by scientists working on the Large Hadron Collider at CERN of the discovery of a Higgs-like particle.

Here are two iPhone pictures of the award:

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In search of Higgs

The link gives an excellent account of the LHC search for Higgs in cartoon form from PHD comics:

Higgs Boson explained by Cartoon

 

 

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