Now, pushing the regime of the very cold into the very small, a research team from the National Institute of Standards and Technology (NIST), the University of Maryland, Janis Research Company, Inc., and Seoul National University, has designed and built the most advanced ultra-low temperature scanning probe microscope (ULTSPM) in the world.
Detailed in a recent paper,* the ULTSPM operates at lower temperatures and higher magnetic fields than any other similar microscope, capabilities that enable the device to resolve energy levels separated by as small as 1 millionth of an electron volt. This extraordinary resolution has already resulted in the discovery of new physics (see "Puzzling New Physics from Graphene Quartet's Quantum Harmonies").
"To get these kinds of measurements, you need to combine coarse and extremely fine movement (the mechanical positioning of a probe tip about two atoms' distance from the sample surface), ultra-high vacuum, cryogenics and vibration isolation," says NIST Fellow Joseph Stroscio, one of the device's co-creators. "We designed this instrument to achieve superlative levels of performance, which, in turn, requires achieving nearly the ultimate in environmental control."
The NIST team had to overcome many technical challenges to achieve this level of precision and sensitivity, according to Young Jae Song, a postdoctoral researcher who helped develop the instrument at NIST.
Past designs used mechanical systems to move the probe tip that did not work over a wide range of temperatures. Researchers overcame this by creating piezoelectric actuators that expand with atomic scale precision when voltage is applied.
For vibration control, the group built the ULTSPM facility on top of a separate 110-ton concrete block buffered by six computer-controlled air springs. The ULTSPM, itself, sits on a 6-ton granite table, isolated from the concrete block by another set of computer-controlled air springs.
To achieve the ULTSPM's ultra low operating temperature of 10 millikelvins, the team designed a low noise dilution refrigerator to supplement the device's chilly 3-meter deep, 250-liter liquid helium bath. Because electromagnetic radiation entering through wires and cables can heat up the microscope, the ULTSPM lab is nested inside a separate, electromagnetically shielded room.
In order to ready new samples and probes without disturbing ongoing measurements, experimenters built a vacuum-sealed "railroad" system that they can disconnect from the chamber.
"The ability to create these kinds of experimental conditions opens up a whole new frontier in nanoscale physics," says Robert Celotta, founding director of the NIST Center for Nanoscale Science and Technology. "This instrument has been five years in the making, and we can't help but be excited about all the discoveries waiting to be made."
* Y. Song, A. Otte, V. Shvarts, Z. Zhao, Y. Kuk, S. Blankenship, A. Band, F. Hess and J. Stroscio. A 10 mK scanning probe microscopy facility. Review of Scientific Instruments. In press.
Mark Esser | Newswise Science News
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering