Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Scientists capture first direct proof of Hofstadter butterfly effect

UCF team Masa Ishigami and Jyoti Katoch work to capture the illusive Hofstadter's butterfly effect.

Credit: UCF
UCF team Masa Ishigami and Jyoti Katoch work to capture the illusive Hofstadter's butterfly effect.

Credit: UCF

Abstract:
A team of researchers from several universities - including UCF -has observed a rare quantum physics effect that produces a repeating butterfly-shaped energy spectrum in a magnetic field, confirming the longstanding prediction of the quantum fractal energy structure called Hofstadter's butterfly.

Scientists capture first direct proof of Hofstadter butterfly effect

Orlando, FL | Posted on May 17th, 2013

This discovery by the team paves the way for engineering new types of extraordinary nanoscale materials that can be used to develop smaller, lighter and faster electronics, including sensors, cell phones, tablets and laptops.

First predicted by American physicist Douglas Hofstadter in 1976, the butterfly pattern emerges when electrons are confined to a two-dimensional plane and subjected to both a periodic potential energy and a strong magnetic field. The Hofstadter butterfly is a fractal pattern—meaning that it contains shapes that repeat on smaller and smaller size scales. Fractals are common in systems such as fluid mechanics, but rare in the quantum mechanical world. The Hofstadter butterfly is one of the first quantum fractals theoretically discovered in physics but, until now, there has been no direct experimental proof of this spectrum.

Columbia University led the study and also involved scientists from the City University of New York, Tohoku University and the National Institute for Materials Science in Japan. Columbia prepared the sample and the UCF team measured the regular recurrence of the high-fidelity periodic pattern, engineered by inducing nanoscale ripples on graphene, a carbon material. The measured recurrence served as the essential proof that the measured spectrum was indeed the Hofstadter butterfly. The image that captured the evidence was taken in UCF Assistant Professor Masa Ishigami's laboratory.

The study is published in today's advance online publication of Nature www.nature.com/nature/journal/vaop/ncurrent/full/nature12186.html

Jyoti Katoch, Ishigami's graduate student, used a non-contact atomic force high-resolution microscope to image the ripples, which have the height of only 0.2 angstroms (twenty trillionth of a meter), to confirm that the observed Hofstadter butterfly spectrum indeed matched the theoretical prediction.

"The arrangement of individual atoms, even just one atom can drastically alter properties of nanoscale materials. That is the basis for nanotechnology," Ishigami said. "Atomic structures must be resolved to understand the properties of nanoscale materials. What we do here at UCF is to explain why nanoscale materials behave so different by resolving their atomic structures. Only when we understand the origin of the extraordinary properties of nanoscale materials, we can propel nanoscience and technology forward. What Jyoti has done here is to image how graphene is rippled to explain the observed Hofstadter spectrum."

UCF's laboratory utilizes a novel, the state-of-the-art microscopy technique to simultaneously determine the atomic structure and electronic properties of nanoscale materials such as graphene.

Katoch has been working with Ishigami since 2008, when Ishigami joined UCF. Katoch helped build the laboratory and developed the atomic-resolution capability critical to capturing the picture proof for this study.

Ishigami has a Ph.D. in physics from the University of California at Berkeley and a bachelor's degree in physics from the Massachusetts Institute of Technology. He has won multiple awards, including the Intelligence Community postdoctoral fellowship and the Hertz graduate fellowship, and has published more than 30 papers in journals including Science.

The College of Sciences, the Nanoscience technology center, and the office of research and commercialization (through a Presidential Initiative to fund major research equipment) supported the purchase and development of the atomic resolution microscope in the Ishigami lab. This research effort was supported by the National Science Foundation under its Faculty Early Career Development Program. (Grant No. 0955625).

####

About University of Central Florida
50 Years of Achievement: The University of Central Florida, the nation's second-largest university with nearly 60,000 students, is celebrating its 50th anniversary in 2013. UCF has grown in size, quality, diversity and reputation, and today the university offers more than 200 degree programs at its main campus in Orlando and more than a dozen other locations. Known as America's leading partnership university, UCF is an economic engine attracting and supporting industries vital to the region's success now and into the future.

For more information, please click here

Contacts:
Zenaida Gonzalez Kotala

407-823-6120

Copyright © University of Central Florida

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Download article:

Related News Press

News and information

Squeezing light at the nanoscale: Ultra-confined light could detect harmful molecules June 17th, 2018

Physicists devise method to reveal how light affects materials: The new method adds to the understanding of the fundamental laws governing the interaction of electrons and light June 15th, 2018

Tripling the Energy Storage of Lithium-Ion Batteries: Scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries June 14th, 2018

New optical sensor can determine if molecules are left or right 'handed' June 13th, 2018

Nickel ferrite promotes capacity and cycle stability of lithium-sulfur battery June 13th, 2018

Imaging

New optical sensor can determine if molecules are left or right 'handed' June 13th, 2018

Nano-saturn: Supramolecular complex formation: Anthracene macrocycle and C60 fullerene June 8th, 2018

Scientists use photonic chip to make virtual movies of molecular motion June 6th, 2018

From Face Recognition to Phase Recognition: Neural Network Captures Atomic-Scale Rearrangements: Scientists use approach analogous to facial-recognition technology to track atomic-scale rearrangements relevant to phase changes, catalytic reactions, and more May 31st, 2018

Physics

Evidence for a new property of quantum matter revealed: Electrical dipole activity detected in a quantum material unlike any other tested June 11th, 2018

Discoveries

Squeezing light at the nanoscale: Ultra-confined light could detect harmful molecules June 17th, 2018

Physicists devise method to reveal how light affects materials: The new method adds to the understanding of the fundamental laws governing the interaction of electrons and light June 15th, 2018

Tripling the Energy Storage of Lithium-Ion Batteries: Scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries June 14th, 2018

Graphene carpets: So neurons communicate better: Research by SISSA reveals that graphene can strengthen neuronal activity, confirming the unique properties of this nanomaterial. The study has been published on Nature Nanotechnology June 13th, 2018

Announcements

Squeezing light at the nanoscale: Ultra-confined light could detect harmful molecules June 17th, 2018

Physicists devise method to reveal how light affects materials: The new method adds to the understanding of the fundamental laws governing the interaction of electrons and light June 15th, 2018

Tripling the Energy Storage of Lithium-Ion Batteries: Scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries June 14th, 2018

New optical sensor can determine if molecules are left or right 'handed' June 13th, 2018

Tools

Nanometrics Updates Time of Webcast at Stifel 2018 Cross Sector Insight Conference June 12th, 2018

Nano-saturn: Supramolecular complex formation: Anthracene macrocycle and C60 fullerene June 8th, 2018

Detecting the birth and death of a phonon June 7th, 2018

Scientists use photonic chip to make virtual movies of molecular motion June 6th, 2018

Quantum nanoscience

Making quantum puddles: Physicists discover how to create the thinnest liquid films ever June 13th, 2018

Detecting the birth and death of a phonon June 7th, 2018

Quantum Interference May Be Key to Smaller Insulators: Breakthrough could jumpstart further miniaturization of transistors June 6th, 2018

Nanoscale measurements 100x more precise, thanks to improved two-photon technique May 8th, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project