Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > When semiconductors stick together, materials go quantum: A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material

The twist angle formed between atomically thin layers of tungsten disulfide and tungsten diselenide acts as a "tuning knob," turning ordinary semiconductors into an exotic quantum material.

CREDIT
Berkeley Lab
The twist angle formed between atomically thin layers of tungsten disulfide and tungsten diselenide acts as a "tuning knob," turning ordinary semiconductors into an exotic quantum material. CREDIT Berkeley Lab

Abstract:
A team of researchers led by the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a simple method that could turn ordinary semiconducting materials into quantum machines - superthin devices marked by extraordinary electronic behavior. Such an advancement could help to revolutionize a number of industries aiming for energy-efficient electronic systems - and provide a platform for exotic new physics.

When semiconductors stick together, materials go quantum: A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material

Berkeley, CA | Posted on March 12th, 2019

The study describing the method, which stacks together 2D layers of tungsten disulfide and tungsten diselenide to create an intricately patterned material, or superlattice, was published online recently in the journal Nature.

"This is an amazing discovery because we didn't think of these semiconducting materials as strongly interacting," said Feng Wang, a condensed matter physicist with Berkeley Lab's Materials Sciences Division and professor of physics at UC Berkeley. "Now this work has brought these seemingly ordinary semiconductors into the quantum materials space."

Two-dimensional (2D) materials, which are just one atom thick, are like nanosized building blocks that can be stacked arbitrarily to form tiny devices. When the lattices of two 2D materials are similar and well-aligned, a repeating pattern called a moiré superlattice can form.

For the past decade, researchers have been studying ways to combine different 2D materials, often starting with graphene - a material known for its ability to efficiently conduct heat and electricity. Out of this body of work, other researchers had discovered that moiré superlattices formed with graphene exhibit exotic physics such as superconductivity when the layers are aligned at just the right angle.

The new study, led by Wang, used 2D samples of semiconducting materials - tungsten disulfide and tungsten diselenide - to show that the twist angle between layers provides a "tuning knob" to turn a 2D semiconducting system into an exotic quantum material with highly interacting electrons.

Entering a new realm of physics

Co-lead authors Chenhao Jin, a postdoctoral scholar, and Emma Regan, a graduate student researcher, both of whom work under Wang in the Ultrafast Nano-Optics Group at UC Berkeley, fabricated the tungsten disulfide and tungsten diselenide samples using a polymer-based technique to pick up and transfer flakes of the materials, each measuring just tens of microns in diameter, into a stack.

They had fabricated similar samples of the materials for a previous study, but with the two layers stacked at no particular angle. When they measured the optical absorption of a new tungsten disulfide and tungsten diselenide sample for the current study, they were taken completely by surprise.

The absorption of visible light in a tungsten disulfide/tungsten diselenide device is largest when the light has the same energy as the system's exciton, a quasiparticle that consists of an electron bound to a hole that is common in 2D semiconductors. (In physics, a hole is a currently vacant state that an electron could occupy.)

For light in the energy range that the researchers were considering, they expected to see one peak in the signal that corresponded to the energy of an exciton.

Instead, they found that the original peak that they expected to see had split into three different peaks representing three distinct exciton states.

What could have increased the number of exciton states in the tungsten disulfide/tungsten device from one to three? Was it the addition of a moiré superlattice?

To find out, their collaborators Aiming Yan and Alex Zettl used a transmission electron microscope (TEM) at Berkeley Lab's Molecular Foundry, a nanoscale science research facility, to take atomic-resolution images of the tungsten disulfide/tungsten diselenide device to check how the materials' lattices were aligned.

The TEM images confirmed what they had suspected all along: the materials had indeed formed a moiré superlattice. "We saw beautiful, repeating patterns over the entire sample," said Regan. "After comparing this experimental observation with a theoretical model, we found that the moiré pattern introduces a large potential energy periodically over the device and could therefore introduce exotic quantum phenomena."

The researchers next plan to measure how this new quantum system could be applied to optoelectronics, which relates to the use of light in electronics; valleytronics, a field that could extend the limits of Moore's law by miniaturizing electronic components; and superconductivity, which would allow electrons to flow in devices with virtually no resistance.

###

Also contributing to the study were researchers from Arizona State University and the National Institute for Materials Science in Japan.

The work was supported by the DOE Office of Science. Additional funding was provided by the National Science Foundation, the Department of Defense, and the Elemental Strategy Initiative conducted by MEXT, Japan, and JSPS KAKENHI. The Molecular Foundry is a DOE Office of Science user facility.

####

About Lawrence Berkeley National Laboratory
Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab's facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy's Office of Science.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

For more information, please click here

Contacts:
Theresa Duque

510-495-2418

Copyright © Lawrence Berkeley National Laboratory

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.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

RELATED JOURNAL ARTICLE:

Related News Press

News and information

Nanometrics to Announce Second Quarter Financial Results on July 30, 2019 July 17th, 2019

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Caught in the act: Images capture molecular motions in real time July 15th, 2019

NUS ‘smart’ textiles boost connectivity between wearable sensors by 1,000 times: Metamaterials are incorporated into conventional clothing to dramatically improve signal strength between electronic devices, allowing for new applications July 15th, 2019

Quantum Physics

Research Reveals Exotic Quantum States in Double-Layer Graphene: Findings shed new light on the nature of electron interactions in quantum systems and establish a potential new platform for future quantum computers June 26th, 2019

Breaking the symmetry in the quantum realm May 31st, 2019

Superconductivity

Researchers report new understanding of thermoelectric materials: Discovery leads to promising new materials for converting waste heat to power June 21st, 2019

Perfect diamagnetism observation of high-temperature superconductivity in compressed H2S June 14th, 2019

UCI scientists create new class of two-dimensional materials: Fabrication could help unlock new quantum computing and energy technologies June 6th, 2019

Govt.-Legislation/Regulation/Funding/Policy

Caught in the act: Images capture molecular motions in real time July 15th, 2019

An 'EpiPen' for spinal cord injuries July 12th, 2019

The best of both worlds: how to solve real problems on modern quantum computers July 12th, 2019

What happens when you explode a chemical bond? Attosecond laser technique yields movies of chemical bond dissociation July 12th, 2019

Possible Futures

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Caught in the act: Images capture molecular motions in real time July 15th, 2019

Dresden physicists use nanostructures to free photons for highly efficient white OLEDs: Trapped light particles July 12th, 2019

Strange warping geometry helps to push scientific boundaries July 12th, 2019

Chip Technology

Nanometrics to Announce Second Quarter Financial Results on July 30, 2019 July 17th, 2019

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Engineers revolutionize molecular microscopy: Single molecules measure electrical potentials July 12th, 2019

'Tsunami' on a silicon chip: a world first for light waves: Sydney-Singapore team manipulates soliton photonic waves on a silicon chip July 5th, 2019

Optical computing/Photonic computing

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Strange warping geometry helps to push scientific boundaries July 12th, 2019

A new way of making complex structures in thin films: Self-assembling materials can form patterns that might be useful in optical devices July 5th, 2019

'Tsunami' on a silicon chip: a world first for light waves: Sydney-Singapore team manipulates soliton photonic waves on a silicon chip July 5th, 2019

Nanoelectronics

Beyond 1 and 0: Engineers boost potential for creating successor to shrinking transistors May 30th, 2019

Laser technique could unlock use of tough material for next-generation electronics: Researchers make graphene tunable, opening up its band gap to a record 2.1 electronvolts May 30th, 2019

From 2D to 1D: Atomically quasi '1D' wires using a carbon nanotube template: New bulk synthesis method for nanowires of molybdenum telluride for nanoelectronics April 19th, 2019

2D borophene gets a closer look: Rice, Northwestern find new ways to image, characterize unique material April 11th, 2019

Discoveries

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Caught in the act: Images capture molecular motions in real time July 15th, 2019

NUS ‘smart’ textiles boost connectivity between wearable sensors by 1,000 times: Metamaterials are incorporated into conventional clothing to dramatically improve signal strength between electronic devices, allowing for new applications July 15th, 2019

Strange warping geometry helps to push scientific boundaries July 12th, 2019

Announcements

Nanometrics to Announce Second Quarter Financial Results on July 30, 2019 July 17th, 2019

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Caught in the act: Images capture molecular motions in real time July 15th, 2019

NUS ‘smart’ textiles boost connectivity between wearable sensors by 1,000 times: Metamaterials are incorporated into conventional clothing to dramatically improve signal strength between electronic devices, allowing for new applications July 15th, 2019

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Breakthrough material could lead to cheaper, more widespread solar panels and electronics July 16th, 2019

Caught in the act: Images capture molecular motions in real time July 15th, 2019

NUS ‘smart’ textiles boost connectivity between wearable sensors by 1,000 times: Metamaterials are incorporated into conventional clothing to dramatically improve signal strength between electronic devices, allowing for new applications July 15th, 2019

An 'EpiPen' for spinal cord injuries July 12th, 2019

Military

Caught in the act: Images capture molecular motions in real time July 15th, 2019

What happens when you explode a chemical bond? Attosecond laser technique yields movies of chemical bond dissociation July 12th, 2019

Sheaths drive powerful new artificial muscles July 11th, 2019

'Hot spots' increase efficiency of solar desalination: Rice University engineers boost output of solar desalination system by 50% June 19th, 2019

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

Sheaths drive powerful new artificial muscles July 11th, 2019

Nanotechnology pioneer Chad Mirkin wins Kabiller Prize in Nanoscience and Nanomedicine: Molly Stevens of Imperial College London receives Kabiller Young Investigator Award July 11th, 2019

'Tsunami' on a silicon chip: a world first for light waves: Sydney-Singapore team manipulates soliton photonic waves on a silicon chip July 5th, 2019

Research Reveals Exotic Quantum States in Double-Layer Graphene: Findings shed new light on the nature of electron interactions in quantum systems and establish a potential new platform for future quantum computers June 26th, 2019

Research partnerships

The best of both worlds: how to solve real problems on modern quantum computers July 12th, 2019

Sheaths drive powerful new artificial muscles July 11th, 2019

Activity of fuel cell catalysts doubled: Modelling leads to the optimum size for platinum fuel cell catalysts July 5th, 2019

Spontaneous synchronisation achieved at the nanoscale July 4th, 2019

Quantum nanoscience

Dresden physicists use nanostructures to free photons for highly efficient white OLEDs: Trapped light particles July 12th, 2019

Research Reveals Exotic Quantum States in Double-Layer Graphene: Findings shed new light on the nature of electron interactions in quantum systems and establish a potential new platform for future quantum computers June 26th, 2019

Mysterious Majorana quasiparticle is now closer to being controlled for quantum computing: Princeton researchers detect a robust Majorana quasiparticle and show how it can be turned on and off June 14th, 2019

2D crystals conforming to 3D curves create strain for engineering quantum devices June 7th, 2019

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project