Navigation Links
NIST researchers holding steady in an atomic-scale tug-of-war
Date:4/1/2010

How hard do you have to pull on a single atom oflet's saygold to detach it from the end of a chain of like atoms?* It's a measure of the astonishing progress in nanotechnology that questions that once would have interested only physicists or chemists are now being asked by engineers. To help with the answers, a research team at the National Institute of Standards and Technology (NIST) has built an ultra-stable instrument for tugging on chains of atoms, an instrument that can maneuver and hold the position of an atomic probe to within 5 picometers, or 0.000 000 000 5 centimeters.**

The basic experiment uses a NIST-designed instrument inspired by the scanning tunneling microscope (STM). The NIST instrument uses as a probe a fine, pure gold wire drawn out to a sharp tip. The probe is touched to a flat gold surface, causing the tip and surface atoms to bond, and gradually pulled away until a single-atom chain (see figure) is formed and then breaks. The trick is to do this with such exquisite positional control that you can tell when the last two atoms are about to separate, and hold everything steady; you can at that point measure the stiffness and electrical conductance of the single-atom chain, before breaking it to measure its strength.

The NIST team used a combination of clever design and obsessive attention to sources of error to achieve results that otherwise would require heroic efforts at vibration isolation, according to engineer Jon Pratt. A fiber-optic system mounted just next to the probe uses the same gold surface touched by the probe as one mirror in a classic optical interferometer capable of detecting changes in movement far smaller than the wavelength of light. The signal from the interferometer is used to control the gap between surface and probe. Simultaneously, a tiny electric current flowing between the surface and probe is measured to determine when the junction has narrowed to the last two atoms in contact. Because there are so few atoms involved, electronics can register, with single-atom sensitivity, the distinct jumps in conductivity as the junction between probe and surface narrows.

The new instrument can be paired with a parallel research effort at NIST to create an accurate atomic-scale force sensorfor example, a microscopic diving-board-like cantilever whose stiffness has been calibrated on NIST's Electrostatic Force Balance. Physicist Douglas Smith says the combination should make possible the direct measurement of force between two gold atoms in a way traceable to national measurement standards. And because any two gold atoms are essentially identical, that would give other researchers a direct method of calibrating their equipment. "We're after something that people that do this kind of measurement could use as a benchmark to calibrate their instruments without having to go to all the trouble we do, " Smith says. "What if the experiment you're performing calibrates itself because the measurement you're making has intrinsic values? You can make an electrical measurement that's fairly easy and by observing conductance you can tell when you've gotten to this single-atom chain. Then you can make your mechanical measurements knowing what those forces should be and recalibrate your instrument accordingly."

In addition to its application to nanoscale mechanics, say the NIST team, their system's long-term stability at the picometer scale has promise for studying the movement of electrons in one-dimensional systems and single-molecule spectroscopy.


'/>"/>

Contact: Michael Baum
michael.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology technology :

1. Researchers use improved nanogenerators to power sensors based on zinc oxide nanowires
2. Researchers identify a gene that may play a key role in atherosclerosis and other diseases
3. Thomson Reuters Names the Worlds Hottest Researchers
4. Cleveland researchers use natural and artificial sheaths to mend traumatic bone loss
5. MIT researchers discover new way of producing electricity
6. Researchers create atlas of transcription factor combinations
7. From 2-trillion-degree heat, researchers create new matter -- and new questions
8. Sorting device for analyzing biological reactions puts the power of a lab in a researchers pocket
9. Researchers gain detailed insight into failing heart cells using new nano technique
10. Dramatic changes in agriculture needed as world warms and grows, researchers say
11. 4 ORNL researchers selected for Recovery Act early career funds
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
NIST researchers holding steady in an atomic-scale tug-of-war
(Date:5/4/2016)... ... May 04, 2016 , ... PBI-Gordon Corporation is pleased to announce Doug Obermann ... began his career at PBI-Gordon in February 1988, after finishing his masters in agronomy ... ranging from customer service to national product manager, to helping develop, name and launch ...
(Date:5/3/2016)... ... 03, 2016 , ... In a list published by the Boston Business Journal, ... private companies; a small percentage of the state's 615,000+ small businesses. The list examined ... in revenue from 2012 to 2015. , As this award comes on ...
(Date:5/3/2016)... ... May 03, 2016 , ... Wearable Tech + Digital ... will take place on June 7-8, 2016, at the New York Academy of Sciences.  ... technology -- including AR/VR, machine learning, apps, robotics and AI -- throughout a major ...
(Date:5/3/2016)... ... May 03, 2016 , ... ... clinics and IVF laboratories. A contingency of reproductive endocrinologists, including Dr. George ... women experiencing infertility and to help them build families. , Ovation Fertility is ...
Breaking Biology Technology:
(Date:3/15/2016)... York , March 15, 2016 ... market report published by Transparency Market Research "Digital Door Lock ... and Forecast 2015 - 2023," the global digital door lock ... 731.9 Mn in 2014 and is forecast to grow at ... Growth of micro, small and medium enterprises (MSMEs) across the ...
(Date:3/11/2016)... http://www.apimages.com ) - --> http://www.apimages.com ) - ... Images ( http://www.apimages.com ) - Germany . ... new refugee identity cards. DERMALOG will be unveiling this device, and ... Hanover next week.   --> Germany ... the new refugee identity cards. DERMALOG will be unveiling this device, ...
(Date:3/9/2016)... NEW YORK , March 9, 2016 ... current and future states of the RNA Sequencing (RNA ... in segments such as instruments, tools and reagents, data ... Analyze various segments of the RNA-Sequencing market such ... RNA-Sequencing services Identify the main factors affecting each segment ...
Breaking Biology News(10 mins):