Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Considering the ‘Anticrystal’

Published: Wednesday, July 09, 2014
Last Updated: Tuesday, July 08, 2014
Bookmark and Share
Researchers have evidence of a new concept, the anticrystal, a theoretical solid that is completely disordered.

For the last century, the concept of crystals has been a mainstay of solid-state physics. Crystals are paragons of order; crystalline materials are defined by the repeating patterns their constituent atoms and molecules make.

Now physicists at the University of Pennsylvania and the University of Chicago have evidence that a new concept should undergird our understanding of most materials: the anticrystal, a theoretical solid that is completely disordered.

Their work suggests that, when trying to understand a real material’s mechanical properties, scientists would be better served in many cases by starting with the framework of the anticrystal and adding order, rather than starting with a perfect crystal and adding disorder. That is because the mechanical properties of even a slightly disordered solid can have more in common with an anticrystal than a perfect crystal.

Understanding these properties is critical for modeling how materials will respond to stress, as well as for designing new materials and predicting their behavior.

The study, published in Nature Physics, was conducted by Andrea Liu, a professor of physics in Penn’s School of Arts & Sciences; Carl Goodrich, a graduate student in her group; and Sidney Nagel, a professor of physics at the University of Chicago.

“One of the reasons the idea of the perfect crystal has been so successful over the last 100 years,” Goodrich said, “is because the properties of an imperfect crystal are often very similar.”

Outside of extremely controlled conditions, no real crystal is perfect; there are always places of disorder within the overall pattern, which are known as defects. However, when describing the behavior of a crystalline material, scientists begin by treating it as if it were a perfect crystal, then extrapolating from that point based on how prevalent its defects actually are. Knowing the exact shape and location of each defect isn’t necessary.

“But if you keep adding disorder, the extrapolation from the perfect crystal fails badly. The mechanical properties can no longer be described well from the perfect crystal. That’s where the anticrystal comes in,” Goodrich said.

Non-crystalline, or amorphous, materials may have regions within them that have atoms in different repeating patterns but no overarching order. This means that the properties of glass or plastic cannot be inferred from a perfect crystal, but working from the other end of the spectrum, a perfectly disordered solid, had not been feasible. Not all disorder is alike; a deck of cards, for example, has one “correct” order but can be shuffled into an astronomically large number of different sequences.

“In the last decade or so,” Liu said, “many researchers have shown that all of those different ways of being totally disordered do have something important in common, like how likely you are to draw a certain hand even given all of the ways you can shuffle a deck of cards.

“We now understand that, for a certain class of interactions, there is a starting point for understanding why different glasses have similar properties,” she said. “It’s the phase transition that occurs when a fluid becomes a disordered solid under pressure, which we call the ‘jamming transition.’”

A phase transition is what happens when one state of matter turns into another, such as when water freezes. A decrease in temperature means that the hydrogen and oxygen atoms of the water no longer have enough energy to bounce out of the six-sided pattern they naturally nestle into. Without being able to move and flow past each other, the hydrogen and oxygen atoms crystallize into solid ice.

Another way of producing a solid, however, is by jamming particles (such as atoms, molecules, or even grains of sand) together, physically constraining their movements under high pressure.

“Anytime you have a critical point like a phase transition, studying the details really close to that transition tells you about how systems further away from the transition behave,” Goodrich said.

By extrapolating away from the jamming transition, the researchers showed that even fairly orderly materials exhibited behaviors closer to those of the anticrystal than a perfect crystal.

“It takes seven shuffles to totally randomize an ordered deck. But suppose you just shuffle it once,” Goodrich said. “What we’re saying is that, when it comes to a materials’ mechanical behavior, even this deck is closer to being totally shuffled than totally ordered.”

“Fifty-two is a large number when thinking about permutations,” Liu said, “but it’s not anywhere close to Avogadro’s number and the different ways all of the atoms in a piece of glass can be arranged.”

Having a better starting point for glass or plastic would be a boon to both research and industrial design, but the principles of the anticrystal are powerful because they can provide insight into many crystalline materials as well. Making alloys like steel stronger often involves making their crystalline patterns smaller and smaller, meaning their behaviors are better and better described by the anticrystal.

“Just as a perfect crystal has very well defined properties,” Liu said, “the anticrystal has well defined properties, and we can think of real materials as being somewhere in between the two. What we’ve shown is that it doesn’t take much disorder before the anticrystal is a better starting point.”


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,500+ scientific posters on ePosters
  • More Than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.


Scientific News
Liquid Biopsies: Utilization of Circulating Biomarkers for Minimally Invasive Diagnostics Development
Market Trends in Biofluid-based Liquid Biopsies: Deploying Circulating Biomarkers in the Clinic. Enal Razvi, Ph.D., Managing Director, Select Biosciences, Inc.
Lab-on-a-Chip Offers Promise for TB and Asthma Patients
A device to mix liquids using ultrasonics is the first and most difficult component in a miniaturized system for low-cost analysis of sputum from patients with pulmonary diseases such as tuberculosis and asthma.
Intracellular Microlasers Could Allow Precise Labeling of up to a Trillion Individual Cells
MGH investigators have induced structures incorporated within individual cells to produce laser light at wavelengths that differ based on the size, shape and composition of each microlaser, allowing precise labeling of individual cells.
Real-Time Imaging of Lung Lesions During Surgery
Targeted molecular agents cause lung adenocarcinomas to fluoresce during surgery, according to pilot report.
Watching a Tumour Grow in Real-Time
Researchers from the University of Freiburg have gained new insight into the phases of breast cancer growth.
Protein Related to Long Term Traumatic Brain Injury Complications Discovered
NIH-study shows protein found at higher levels in military members who have suffered multiple TBIs.
Childhood Cancer Cells Drain Immune System’s Batteries
Cancer cells in neuroblastoma contain a molecule that breaks down a key energy source for the body’s immune cells, leaving them too physically drained to fight the disease.
Urine Proteins Point to Early-Stage Pancreatic Cancer
A combination of three proteins found at high levels in urine can accurately detect early-stage pancreatic cancer, researchers at the BCI have shown.
Researcher Discovers Trigger of Deadly Melanoma
New research sheds light on the precise trigger that causes melanoma cancer cells to transform from non-invasive cells to invasive killer agents, pinpointing the precise place in the process where "traveling" cancer turns lethal.
New Vaccine For Chlamydia to Use Synthetic Biology
Prokarium Ltd, a biotechnology company developing transformational oral vaccines, have announced new funding from SynbiCITE, the UK’s Innovation and Knowledge Centre for Synthetic Biology.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!