Tag archives: condensed matter
By James Dacey in Beijing on Friday 4 November
After enjoying clear blue skies for the first couple of days of my visit to Beijing, the breeze has disappeared and the smog has taken its hold. One local scientist told me this latest wave is due to pollution from factories south-west of the city, but others have told me it is difficult to pinpoint a particular source. Facemasks are being worn by every other person in the streets, but fortunately I’ve been sheltered by the walls and ceilings of Peking University (PKU).
By Hamish Johnston in Beijing
This morning I had a wonderful visit to see some condensed-matter physicists at the Institute of Physics of the Chinese Academy of Sciences (IOP CAS). First I met with theorists Zhong Fang and Hongming Weng and if you know your equations you can see from the above photo that they work on Weyl semi-metals. Fang is deputy director of the institute and is head of a theoretical physics group that includes six faculty members and about 20 postgraduate students. Avid readers might recall that Fang and Weng were named in the Physics World Top 10 Breakthroughs of 2015 for their work on Weyl fermions.
By Matin Durrani in Beijing, China
The last couple of days in the Chinese capital have been unusually damp and cool for the middle of June. Today, however, dawned sparklingly sunny as I headed off with my colleague Mingfang Lu from the Beijing office of the Institute of Physics, which publishes Physics World, to the Beijing Computational Science Research Center (CSRC) on the outskirts of the city.
Located on a shiny new software park, this sleek, five-storey building opened in March last year and looks just how you might expect the headquarters of IKEA to be – all minimalist corridors, big glass windows and the odd work of art dotted around. There’s even a fitness room in the basement. It’s currently got 43 full-time faculty, a third of whom are physicists, making this 45,000 m2 building – roughly the size of seven football pitches – seem remarkably sparse.
By Michael Banks in Shenzhen, Guangdong province, China
It is well documented how China seems to be able to build cities within weeks. But how quickly could it build its very own Silicon Valley?
Well, that question may well be answered very soon. Today, I was at the South University of Science and Technology of China (SUSTC), which is located in Shenzhen, Guangdong province.
The university was only created in 2011 and currently the physics department has a sole focus on experimental and theoretical condensed-matter physics, with around 20 undergraduate students each year (that number is expected to rise as the department expands into other areas of physics).
By Tushna Commissariat in Baltimore, Maryland, US
One of the most popular talks this morning at the APS March meeting was almost certainly given by Nobel-prize-winning physicist Anthony Leggett of the University of Illinois at Urbana-Champaign in the US. Leggett, who shared the 2003 Nobel Prize for Physics for his work on superconductors and superfluids, talked about his “Reflections on the past present and future of of condensed-matter physics”.
As the abstract of his talk suggests, Leggett looked at the ways, means and even the very definition of “condensed-matter physics” has changed and “evolved since its inception in the early 20th century, with particular reference to its relationship to neighbouring and even distant disciplines”. He went on to “speculate on some possible directions in which the discipline may develop over the next few decades, emphasizing that there are still some very basic questions to which we currently have no satisfactory answers”.
I missed the beginning of his talk as I was attending the morning’s first set of press briefings (more on those later) but when I did walk into the packed hall for his talk, his slide had the rather interesting title: “Would I encourage my grandchildren to go into condensed-matter physics?” Happlily enough, his answer at the end of his talk was a resounding “yes”.
By Matin Durrani and Tushna Commissariat in Baltimore, Maryland, US
So here we are in Baltimore to attend the 2016 March meeting of the American Physical Society (APS). We’re writing this at the window seats in a burrito bar on Pratt Street while staring at the hulk that is the Baltimore Convention Center, where nigh-on 10,000 physicists will be congregating all week.
We’ve been playing a game of “spot the APS attendee” while tucking into our burritos. Without wishing to stereotype physicists (okay, go on then, we will) they’re the ones with the backpacks stuffed with poster tubes, pulling little trolley suitcases, looking lost before veering towards the convention centre.
There are also some physicists inside Chipotle Mexican Grill – you can tell because they’re huddled around laptops looking at PowerPoint presentations showing graphs of Fermi surfaces and topological insultators. Probably not the usual subject of discussion in here.
By Hamish Johnston
Condensed matter is a physicist’s paradise because of the seemingly endless number of ways that atoms can be rearranged to create systems with new and exciting behaviours. A great example of this is the emerging field of “valleytronics”, which is concerned with a property of electrons that emerges in some semiconductors and 2D materials such as graphene.
The eponymous valley is a local minimum in the conduction band of a solid that “traps” electrons into a specific momentum state. Things get interesting when a material has two valleys that result in two distinct momentum states. In some materials these states resemble the quantum-mechanical property of spin: an electron can be in one of two spin states (up or down) and it can also be in one of two momentum states. As a result, this property is sometimes referred to as valley pseudospin.
By Tushna Commissariat
Spintronics is often touted to be a field of research that one day soon will revolutionize computing as we know it, helping build the next generation of superfast and energy-efficient computers that we long for. Future spintronic devices will tap into the inherent spin magnetic moment of the electron, rather than just its charge, to store and process information. As an electron’s spin can be flipped much quicker than its charge can be moved, these devices should, in theory, operate faster and at lower temperatures than their current electronic-only counterparts.
The entire basis of this field is built on research done by Soviet-American theoretical physicist Emmanuel Rashba in 1959. Indeed, he was the first to discover the splitting of the spin-up and spin-down states in energy and momentum with an applied electric field instead of a magnetic field. But Rashba’s original article detailing the effect, written together with Valentin Sheka, was published in a supplement of the Soviet-era, Russian-language journal, Fizika Tverdogo Tela, and is nearly impossible to get a hold of today.
New Journal of Physics (which is published by IOP Publishing, which also publishes Physics World) has now produced a focus collection of articles on the Rashba effect. As a part of this collection, guest editors Oliver Rader of the Helmholtz Centre Berlin, Gustav Bihlmayer of the Jülich Research Centre in Germany and Roland Winkler of the Northern Illinois University in the US worked with Rashba to create an English-language version of his original paper.
You can access the entire “Focus on the Rashba Effect” collection here, and the translated original paper here. In some ways, this highlights the importance of other key research articles that may have been published in journals that are no longer available and so may be in danger of being lost forever. Leave us a comment if you can think of any such papers.
By Anna Demming, online editor of nanotechweb.org
Last month on a rainy grey morning in north-east England I headed to the Daresbury Laboratory as the SuperSTEM lab there celebrated the installation of its latest world-class microscope. Industrial and academic microscopists from around the world gathered for the inauguration, which was described as a “wedding for microscopists” because so many people from the tightly knit microscopy community were there. You can hear the excitement in the audio piece below, where SuperSTEM lab director Quentin Ramasse and other researchers at the event tell me their plans for the new instrument.
By Tushna Commissariat
Physics experiments are not normally the stuff of “viral” videos on the Internet, but that is precisely what happened when physics students at the University of Bath in the UK decided to get creative with the Leidenfrost effect. If you are a regular reader of Physics World, you may get that déjà vu feeling when you watch the video above of water droplets zipping about the “Leidenfrost maze” built by (at the time undergraduates) Carmen Cheng and Matthew Guy – but rest assured you have seen it right here on this blog in 2013 when editor Hamish Johnston wrote about it before it amassed a whopping 120,150 views on YouTube.