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Primeur weekly 2020-01-13

Focus

Ambitious plans for e-IRG, EOSC and EuroHPC under Croatian EU Presidency - Interview with Ivan Maric, SRCE, Croatia ...

Quantum computing

Delta partners with IBM to explore quantum computing - an airline industry first ...

IBM working with over 100 organisations to advance practical quantum computing ...

New quantum loop provides long national testbed for quantum communication technology ...

The case of the elusive Majorana: The so-called 'angel particle' is still a mystery ...

World's first quantum-safe connected car secured by ISARA ...

Georgia Tech collaborates with IBM to develop software stacks for quantum computers ...

New York University partners with IBM to explore quantum computing for simulation of quantum systems and advancing quantum education ...

Focus on Europe

Barcelona Supercomputing Center coordinates the manufacture of the first open source chip developed in Spain ...

Atos empowers researchers at the University of Luxembourg with its BullSequana XH2000 supercomputer ...

Solemn inauguration of the HLRN-IV system ...

The European Commission is looking for IT specialists in HPC, Quantum, Infrastructure and Cloud ...

Dr. Alice-Agnes Gabriel wins 2020 PRACE Ada Lovelace Award for HPC ...

Middleware

Altair acquires newFASANT, further expanding high-frequency electromagnetics portfolio ...

Hardware

ECMWF signs contract with Atos for new supercomputer ...

World High Performance Computing (HPC) markets to 2025 - AI, IoT, and 5G will be major drivers for HPC growth as they facilitate the need to process vast amounts of data ...

IDC MarketScape names WekaIO as a major player in file-based storage ...

200G HDR InfiniBand to accelerate the new European Centre for Medium-Range Weather Forecasts (ECMWF) supercomputer ...

Applications

Frederick National Laboratory part of SC19 "Best Paper" team ...

Hyperion Research expands its analyst team ...

Supercomputer simulations showcase novel planet formation models ...

Satellite constellations harvest energy for near-total global coverage ...

Exploring the 'dark side' of a single-crystal complex oxide thin film ...

Sublimation, not melting: Graphene surprises researchers again ...

Persistence of gut microbial strains in twins, living apart after cohabitating for decades ...

Kun Sun and Sushil Jajodia receive funding for subcontract agreement ...

Decrappifying brain images with deep learning ...

Xylem expands regional headquarters in Singapore with new Technology Hub ...

The Cloud

Intel brings innovation to life with intelligent tech spanning the Cloud, network, edge and PC at CES 2020 ...

Los Alamos National Laboratory joins IBM Q Network to explore quantum computing algorithms and education outreach ...

Sublimation, not melting: Graphene surprises researchers again


Abstraction. Credit: MIPT.
6 Jan 2020 Moscow - Physicists from the Moscow Institute of Physics and Technology and the Institute for High Pressure Physics of the Russian Academy of Sciences have used computer modelling to refine the melting curve of graphite that has been studied for over 100 years, with inconsistent findings. They also found that graphene 'melting' is in fact sublimation. The results of the study came out in the journalCarbon.

Graphite is a material widely used in various industries - for example in heat shields for spacecraft - so accurate data on its behavior at ultrahigh temperatures is of paramount importance. Graphite melting has been studied since the early 20thcentury. About 100 experiments have placed the graphite melting point at various temperatures between 3000 and 7000 kelvins. With a spread so large, it is unclear which number is true and can be considered the actual melting point of graphite. The values returned by different computer models are also at variance with each other.

A team of physicists from MIPT and HPPI RAS compared several computer models to try and find the matching predictions. Yuri Fomin and Vadim Brazhkin used two methods: classical molecular dynamics and ab initio molecular dynamics. The latter accounts for quantum mechanical effects, making it more accurate. The downside is that it only deals with interactions between a small number of atoms on short time scales. The researchers compared the obtained results with prior experimental and theoretical data.

Yuri Fomin and Vadim Brazhkin found the existing models to be highly inaccurate. But it turned out that comparing the results produced by different theoretical models and finding overlaps can provide an explanation for the experimental data.

As far back as 1960s, the graphite melting curve was predicted to have a maximum. Its existence points to complex liquid behavior, meaning that the structure of the liquid rapidly changes on heating or densification. The discovery of the maximum was heavily disputed, with a number of studies confirming and challenging it over and over. Yuri Fomin and Vadim Brazhkin's results show that the liquid carbon structure undergoes changes above the melting curve of graphene. The maximum therefore has to exist.

The second part of the study is dedicated to studying the melting of graphene. No graphene melting experiments have been conducted. Previously, computer models predicted the melting point of graphene at 4500 or 4900 K. Two-dimensional carbon was therefore considered to have the highest melting point in the world.

"In our study, we observed a strange 'melting' behaviour of graphene, which formed linear chains. We showed that what happens is it transitions from a solid directly into a gaseous state. This process is called sublimation", commented Associate Professor Yuri Fomin of the Department of General Physics, MIPT. The findings enable a better understanding of phase transitions in low-dimensional materials, which are considered an important component of many technologies currently in development, in fields from electronics to medicine.

The researchers produced a more precise and unified description of how the graphite melting curve behaves, confirming a gradual structural transition in liquid carbon. Their calculations show that the melting temperature of graphene in an argon atmosphere is close to the melting temperature of graphite.

The study was supported by the Russian Science Foundation and used the computing resources of the Complex for Simulation and Data Processing for Mega-Science Facilities, a federal centre of shared research facilities at Kurchatov Institute.

Source: Moscow Institute of Physics and Technology - MIPT

Back to Table of contents

Primeur weekly 2020-01-13

Focus

Ambitious plans for e-IRG, EOSC and EuroHPC under Croatian EU Presidency - Interview with Ivan Maric, SRCE, Croatia ...

Quantum computing

Delta partners with IBM to explore quantum computing - an airline industry first ...

IBM working with over 100 organisations to advance practical quantum computing ...

New quantum loop provides long national testbed for quantum communication technology ...

The case of the elusive Majorana: The so-called 'angel particle' is still a mystery ...

World's first quantum-safe connected car secured by ISARA ...

Georgia Tech collaborates with IBM to develop software stacks for quantum computers ...

New York University partners with IBM to explore quantum computing for simulation of quantum systems and advancing quantum education ...

Focus on Europe

Barcelona Supercomputing Center coordinates the manufacture of the first open source chip developed in Spain ...

Atos empowers researchers at the University of Luxembourg with its BullSequana XH2000 supercomputer ...

Solemn inauguration of the HLRN-IV system ...

The European Commission is looking for IT specialists in HPC, Quantum, Infrastructure and Cloud ...

Dr. Alice-Agnes Gabriel wins 2020 PRACE Ada Lovelace Award for HPC ...

Middleware

Altair acquires newFASANT, further expanding high-frequency electromagnetics portfolio ...

Hardware

ECMWF signs contract with Atos for new supercomputer ...

World High Performance Computing (HPC) markets to 2025 - AI, IoT, and 5G will be major drivers for HPC growth as they facilitate the need to process vast amounts of data ...

IDC MarketScape names WekaIO as a major player in file-based storage ...

200G HDR InfiniBand to accelerate the new European Centre for Medium-Range Weather Forecasts (ECMWF) supercomputer ...

Applications

Frederick National Laboratory part of SC19 "Best Paper" team ...

Hyperion Research expands its analyst team ...

Supercomputer simulations showcase novel planet formation models ...

Satellite constellations harvest energy for near-total global coverage ...

Exploring the 'dark side' of a single-crystal complex oxide thin film ...

Sublimation, not melting: Graphene surprises researchers again ...

Persistence of gut microbial strains in twins, living apart after cohabitating for decades ...

Kun Sun and Sushil Jajodia receive funding for subcontract agreement ...

Decrappifying brain images with deep learning ...

Xylem expands regional headquarters in Singapore with new Technology Hub ...

The Cloud

Intel brings innovation to life with intelligent tech spanning the Cloud, network, edge and PC at CES 2020 ...

Los Alamos National Laboratory joins IBM Q Network to explore quantum computing algorithms and education outreach ...