Scientists investigate voltage drop with sub-nanometer resolution
Scientists from the Universities of Göttingen and Erlangen have made an important step towards a deeper understanding of smallest resistances. Using a scanning tunnelling microscope, the researchers succeeded in resolving the spatial extent of a voltage drop with sub-nanometer resolution for the first time. Their results were published in Nature Communications.
The physicists investigated the relationship between the voltage drop and resistance on the atomic scale. As their sample system they used graphene, a single layer of hexagonally oriented carbon atoms.
In their experiments, a current-carrying layer of graphene showed the expected linear voltage drop in defect-free regions of the sample. This is in contrast to the behaviour at local defects, for example the transition between layers: These transitions form barriers where the electrons are reflected, which leads to an abrupt voltage drop.
“Our findings show that the voltage drop is much greater in size than the actual defect,” explains doctoral candidate Philip Willke from Göttingen University’s IV. Physical Institute.
“Furthermore, we observed that the voltage drop is located almost completely in the bilayer. This problem can be compared to a highway that changes from two lanes to only one. The lane change, or in this case the change from one layer of graphene to the other, is extremely hard for the electrons.”
“Our results demonstrate that it is possible to characterise electron transport in non-equilibrium on the atomic scale and to distinguish between different scattering contributions,” adds Dr. Martin Wenderoth, head of the group.
“So far, this was only possible by theoretical calculations. Our findings will help to prove current theories and to establish a deeper understanding of electron transport itself.”
Original publication: Philip Willke et al. Spatial extent of a Landauer residual-resistivity dipole in graphene quantified by scanning tunnelling potentiometry. Nature Communications 2015. Doi: 10.1038/ncomms7399.
Dr. Martin Wenderoth
University of Göttingen
Faculty of Physics – IV. Physical Institute
Friedrich-Hund-Platz 1, 37077 Göttingen
Phone +49 551 39-9367 or -4536
Thomas Richter | Georg-August-Universität Göttingen
Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie
Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy