The quantum Hall effect was previously believed to only be observable at temperatures close to absolute zero (equal to minus 459 degrees). But when scientists at the National High Magnetic Field Laboratory in the U.S. and at the High Field Magnet Laboratory in the Netherlands put a recently developed new form of carbon called graphene in very high magnetic fields, scientists were surprised by what they saw.
"At room temperature, these electron waves are usually destroyed by the jiggling atoms and the quantum effects are destroyed," said Nobel Prize winner Horst Stormer, physics professor at Columbia University and one of the paper's authors. "Only on rare occasions does this shimmering quantum world survive to the temperature scale of us humans."
The quantum Hall effect is the basis for the international electrical resistance standard used to characterize even everyday materials that conduct electricity, such as the copper wires in a home. It was first discovered in 1980 by the German physicist Klaus von Klitzing, who was awarded a Nobel Prize in 1985 for his discovery. Until recently the quantum Hall effect was considered to belong to the realm of very low temperatures.
That opinion began to change, however, with the ability to create very high magnetic fields and with the discovery of graphene, a single atomic sheet of atoms about as strong as diamond. Together, these two things have allowed scientists to push this fragile quantum effect all the way to room temperature. Now there is a way to see curious and often surprising quantum effects, such as frictionless current flow and resistances as accurate as a few parts per billion, even at room temperature.
The research was carried out by scientists from the University of Manchester in England, Columbia University in New York, the National High Magnetic Field Laboratory in Tallahassee, Florida, the High Field Magnet Laboratory in Nijmegen, Netherlands, and the Foundation for Fundamental Research on Matter, also in the Netherlands. Their article appears in Science Express, the advanced online publication of Science magazine, a top American journal with international stature.
The scientists believe that these findings may one day lead to a compact resistance standard working at elevated temperatures and magnetic fields that are easily attainable at the National High Magnetic Field Laboratory.
"The more we understand the strange world of quantum physics, the better we can design the next generation of ultra-small electrical devices, which already are pushing into the quantum regime," said Gregory S. Boebinger, director of the U.S. magnet lab.
"This is a really amazing discovery for a quantum Hall physicist," said Uli Zeitler, senior scientist at the High Field Magnet Laboratory. "For more than two decades, we've focused our research on exploring new frontiers such as very low temperatures and extremely sophisticated materials, and now it appears that we can just measure a quantum Hall effect in a pencil-trace and at room temperature."
The room temperature quantum Hall effect was discovered independently in the two high field labs, in the 45-tesla Hybrid magnet in Tallahassee and in a 33-tesla resistive magnet in Nijmegen. Both research groups agreed that a common announcement on both sides of the Atlantic was the right thing to do.
"Because so many scientists are exploring this exciting new material, we are all on this roller coaster together," said Boebinger. "Sometimes it makes sense to put competitiveness aside and write a better paper together."
Susan Ray | EurekAlert!
NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center
Researchers create artificial materials atom-by-atom
28.03.2017 | Aalto University
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy