New energy pattern observed at National High Magnetic Field Laboratory
2013 05 17

By Thomas Anderson | TGDaily

Two research teams at the National High Magnetic Field Laboratory (MagLab) smashed through a nearly 40-year barrier recently when they observed a never-before-seen energy pattern.

The butterfly-shaped pattern was first theorized by physicist Douglas Hofstadter in 1976, but it took the tools and technology now available at the MagLab to prove its existence.

"The observation of the ’Hofstadter butterfly’ marks a real landmark in condensed matter physics and high magnetic field research," said Greg Boebinger, director of the MagLab. "It opens a new experimental direction in materials research."

This groundbreaking research demanded the ability to measure samples of materials at very low temperatures and very high magnetic fields, up to 35 tesla. Both of those conditions are available at the MagLab, making it an international destination for scientific exploration.

The unique periodic structure used to observe the butterfly pattern was composed of boron nitride (BN) and graphene. Graphene is a Nobel Prize-winning material that holds tremendous promise in revolutionizing computers, batteries, cell phones, televisions and even airplanes. A one-atom thick, honeycomb array of carbon atoms, graphene is virtually see-through, yet 300 times stronger than steel and 1,000 times more conducting than silicon.

"This is about a puzzle that has been solved," said Eric Palm, deputy director at the MagLab. "It is really about scientific curiosity. It is an exciting confirmation of a theory that was made years ago."

MagLab physicist Nicholas Bonesteel agreed, adding "The Hofstadter butterfly is a beautiful fractal energy pattern that has intrigued physicists for decades. Seeing clear experimental evidence for it is a real breakthrough."

[...]

Read the full article at: tgdaily.com




What the teams did was place graphene – a layer of carbon just one atom thick – on an extremely flat surface of a boron-nitride crystal. As both materials have similar hexagonal structures, the researchers observed "Moiré patterns", which are regular patterns created whenever two similar 2D lattices are overlaid. (The Manchester and MIT groups used single-layer graphene, while the Columbia-led experiment involved bilayer graphene.) By tweaking the relative orientation of the two lattices, the teams were able to create superlattices with appropriate spacing. Source


Butterfly seen at long last





Related Articles
Nature: Hofstadter’s butterfly and the fractal quantum Hall effect in moiré superlattices
Scientists use magnetic nano-rods to investigate how matter assembles
New Discovery Provides Unprecedented Control of Magnetic Fields


Latest News from our Front Page

If Someone Secretly Controlled What You Say, Would Anyone Notice?
2014 10 01
The subject enters a room in which a 12-year-old boy is seated. A 20-minute conversation ensues. The subject quizzes the boy about current events and other topics to get a sense of his intelligence and personality. But the boy is not what he appears to be. Unbeknownst to the subject, the boy is wearing a radio receiver in his ear, and ...
Obama has had accurate intelligence about ISIS since BEFORE the 2012 election, says administration insider
2014 10 01
‘President Barack Obama’s intelligence briefings have provided him with specific information since before he won re-election in 2012 about the growing threat of the terror group now known alternatively as ISIS and ISIL, an administration insider told MailOnline on Monday. ‘Unless someone very senior has been shredding the president’s daily briefings and telling him that the dog ate them, highly accurate ...
Can holding a magnet against your head help defeat depression?
2014 10 01
Former GP Sue Mildred suffered from crippling depression and anxiety for 20 years. On two occasions it was so severe that she ended up in hospital, and for 15 years she was unable to work. Sue, 51, has tried antidepressants, talking therapies and, out of desperation, even ECT (electro-convulsive therapy), where an electric current is passed through the brain. This did ...
Extremists to have Facebook and Twitter vetted by anti-terror police
2014 09 30
Theresa May to announce new Extremist Disruption Orders to strengthen counter-terrorism if the Tories win the next general election Extremists will have to get posts on Facebook and Twitter approved in advance by the police under sweeping rules planned by the Conservatives. They will also be barred from speaking at public events if they represent a threat to “the functioning of democracy”, ...
Scottish Independence: Protesters demand revote
2014 09 30
Pro-independence campaigners gathered outside the Scottish Parliament for the second day in a row, this time to demand a revote of the September 18 referendum. While yesterday’s “Rally For A Revote” saw the return of Saltires and Yes banners to Holyrood, it did not match the turnout for the “Voice Of The People” rally held on Saturday, when up 3000 people ...
More News »