Home > Press > More is less in novel electronic material: Adding electrons actually shrinks the system
Abstract:
Add water to a half-filled cup and the water level rises. This everyday experience reflects a positive material property of the water-cup system. But what if adding more water lowers the water level by deforming the cup? This would mean a negative compressibility.
Now, a quantum version of this phenomenon, called negative electronic compressibility (NEC), has been discovered, a team of researchers led by physicists at Boston College reports today in the online edition of the journal Nature Materials.
Physicists have long theorized that NEC-- an electron system lowering its highest energy level and effectively shrinking its overall size when electrons are added--could in principle be found in quantum materials with non-rigid band structures. Nevertheless, rare experimental realizations of NEC have been limited to the two-dimensional boundaries between certain materials, but never in any three-dimensional (3D) material.
The first experimental evidence of 3D NEC was discovered using the unique material iridium oxide, which belongs to a class of "correlated" materials in which electrons move in an orchestrated fashion. Here, the addition of an electron to the system has a significant impact on the motion of the other electrons, and changes the overall band structure of the material - like the deformed water cup - a prerequisite for NEC.
The researchers experimented with iridium oxide samples synthesized by Boston College (BC) graduate student Tom Hogan, working in the lab of former BC and current University of California, Santa Barbara, Assistant Professor Stephen Wilson.
The observation was made by adding electrons to this material and then studying its band structure with a high precision, advanced spectroscopy technique. The study was performed mainly at the SLAC National Accelerator Laboratory and Lawrence Berkeley National Laboratory in California, and was led by postdoctoral researcher Junfeng He and graduate student Thomas Mion, researchers in the lab of BC Assistant Professor of Physics Rui-Hua He, a lead author of the paper.
By comparing with another correlated material, one that exhibits high-temperature superconductivity but not NEC, coauthors at Northeastern University, including graduate student Hasnain Hafiz and Professors Arun Bansil and Robert Markiewicz, believe they've obtained clues as to what makes the iridium oxide unique in terms of the long-sought occurrence of 3D NEC.
"This is a collective achievement that could not have been made without such a close collaboration of leading experts, within and outside BC," said Michael J. Naughton, chairman of BC Department of Physics and a coauthor on the paper.
"Our finding might open the door to uncharted territory in the area of negative compressibility, which potentially features a whole variety of bulk correlated metals," said He.
Co-author and BC Professor Krzysztof Kempa added that the 3D NEC materials may enable new research into terahertz optics and unique applications in areas such as metamaterials, pushing beyond the scope of two-dimensional systems that display NEC.
This discovery serves as a stepping-stone for the team's ongoing effort to theoretically understand 3D NEC in quantum materials, and to experimentally probe 3D NEC in different ways.
####
For more information, please click here
Contacts:
Ed Hayward
617-552-4826
Copyright © Boston College
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related News Press |
News and information
Researchers develop artificial building blocks of life March 8th, 2024
Physics
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
Scientists use heat to create transformations between skyrmions and antiskyrmions January 12th, 2024
Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024
Laboratories
A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024
NRL discovers two-dimensional waveguides February 16th, 2024
Govt.-Legislation/Regulation/Funding/Policy
What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
Discoveries
What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
High-tech 'paint' could spare patients repeated surgeries March 8th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Materials/Metamaterials/Magnetoresistance
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024
Announcements
What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Researchers develop artificial building blocks of life March 8th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Research partnerships
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
Development of zinc oxide nanopagoda array photoelectrode: photoelectrochemical water-splitting hydrogen production January 12th, 2024
Quantum nanoscience
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
Bridging light and electrons January 12th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||