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Physicists Discover the “secret Source” Behind the Exotic Properties of New Quantum Materials

Taylor Johnston

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Visualization of zero-energy electronic states from Kagome materials studied by MIT’s Riccardo Comin and colleagues-also known as the “Fermi surface”. Credits: Massachusetts Institute of Technology Comin Laboratory

MIT physicists and colleagues have discovered the “secret source” behind some of the exotic properties of new quantum materials that have fixed physicists for these properties, including superconductivity. Theorists have predicted the reasons for the anomalous properties of the material known as Kagome metal, but this is the first time that the phenomena behind these properties have been observed in the laboratory.

“Hope is a new understanding of electronic structure Kagome Metals help us build a rich platform for discovering others Quantum materialHe was an assistant professor of career development in physics at MIT in the 1947 class, and the group led the research. This has the potential to introduce new classes of superconductors, new approaches to quantum computing, and other quantum technologies.

The work is reported in the January 13, 2022 online version of the journal. Nature Physics..

Classical physics can be used to explain many of the underlying phenomena of our world until things get very small. Subatomic particles, such as electrons and quarks, behave differently in ways that are not yet fully understood. Enter quantum mechanics, an area that seeks to explain their behavior and the resulting effects.

Kagome metal, which is at the center of current research, is a new quantum material, or exhibits the exotic properties of quantum mechanics on a macroscopic scale. In 2018, MIT Mitsui Career Development Associate Professors Comin and Joseph Checkelsky led the first research on the electronic structure of Kagome metals, raising interest in this material family. Members of the Kagome Metal family consist of layers of atoms arranged in repeating units similar to the Star of David and the Sheriff’s badge. This pattern is also common in Japanese culture, especially as a basket weaving motif.

“This new family of materials is unconventional, superconducting, nematic, Charge density wave“Comin says.

Abnormal characteristics

A hint of superconductivity and charge density wave ordering for a new family of Kagome metals studied by Comin et al. Was found in the laboratory of Professor Stephen Wilson at the University of California, Santa Barbara. Single crystals were also synthesized there (Wilson said the Nature Physics paper). The specific Kagome material being investigated in the current study is composed of only three elements (cesium, vanadium, antimony) and has a chemical formula of CsV3Sb5.

Researchers have focused on two exotic properties that Kagome metals exhibit when cooled below room temperature. At these temperatures, the electrons in the material begin to exhibit collective behavior. “They don’t move independently, they talk to each other,” says Komin.

One of the resulting properties is superconductivity, which allows the material to conduct electricity very efficiently. In ordinary metal, the electrons behave like people dancing individually in a room. In Kagome superconductors, when the material is cooled to 3 Kelvin (~ -454 degrees Fahrenheit), the electrons start to move in pairs, like a couple of dances. “And all of these pairs are moving together, as if they were part of a quantum choreography,” says Comin.

At 100 Kelvin, the Kagome material studied by Comin and co-workers exhibits yet another strange kind of behavior known as charge density waves. In this case, the electrons are arranged in the shape of ripples like dunes. “They don’t go anywhere. They stay in place,” Komin says. Ripple peaks represent electron-rich regions. The valley is electron deficient. “Charge density waves are very different from superconductors, but they are still a state of matter in which electrons must be arranged in a collective and highly organized manner. They form choreography again, but are no longer dancing. No. Now they form a static pattern. “

Comin states that Kagome metals are of great interest to physicists because they can exhibit both superconducting and charge density waves. “It is unusual for a material to host both, as these two exotic phenomena often compete with each other.”

Secret sauce?

But what’s behind the emergence of these two properties? “What causes electrons to start talking to each other and influencing each other? That’s an important question,” said Mingu Kang, a graduate student in the MIT Physics Department who also belongs to the Max Planck POSTECH Korea Research Initiative. I am saying. .. That’s what physicists report in Nature Physics. “By examining the electronic structure of this new material, we discovered that electrons exhibit an interesting behavior known as electron specificity,” says Kang. This particular singularity is named after Leon van Hove, the Belgian physicist who first discovered it.

The Van Hove singularity contains the relationship between electron energy and velocity. Normally, the energy of a moving particle is proportional to the square of its velocity. “It’s a fundamental pillar of classical physics, [essentially] The faster the speed, the more energy there is. ” Imagine a Red Sox pitcher hitting you with a fastball. Next, imagine your child trying to do the same. Pitcher balls are much more painful than children. There is little energy.

The Comin team has found that with Kagome metal, this rule no longer holds. Instead, electrons moving at different velocities happen to have the same energy. As a result, the pitcher’s fastball has the same physical effect as a child. “It’s very counter-intuitive,” says Comin.He pointed out that it is difficult to relate energy to the velocities of electrons in solids and requires special equipment at two international synchrotron research facilities: Beamline 4A1 of the Urano light source and Lawrence Berkeley. Beamline of Advanced Light Source 7.0.2 (MAESTRO) National Laboratory

Comment Professor Ronny Thomale of the University of Würzburg (Germany): “Theoretical physicists (including my group) predict the unique properties of the Van Hove singularity on the Kagome lattice, which is a crystal structure made up of triangles that share angles. The first experimental validation of these theoretical proposals. “Thomale was not involved in the work.

It is known that if there are many electrons at once in a material with the same energy, they interact much more strongly. As a result of these interactions, the electrons can be paired into superconductivity or otherwise form a charge density wave. “The existence of the Van Hove singularity in materials that have both as a common source of these exotic phenomena makes perfect sense,” Kang adds. “Therefore, the existence of this singularity is the” secret source “that enables the quantum behavior of Kagome metals. “

The team’s new understanding of the relationship between energy and velocity in Kagome materials “is also important because it makes it possible to establish new design principles for the development of new quantum materials,” says Comin. In addition, “We now know how to find this singularity in other systems.”

Direct feedback

When physicists are analyzing data, they often need to process it before they see a clear trend. However, the Kagome system “provided direct feedback on what was happening,” says Comin. “The best part of this study was that we were able to see singularities in the raw data.”

Kagome lattice superconductor reveals “cascade” of quantum electronic states

For more information:
Mingu Kang et al, The origin of the double Van Hove singularity and charge order in the topological Kagome superconductor CsV3Sb5, Nature Physics (2022). DOI: 10.1038 / s41567-021-01451-5

Quote: Physicist, new quantum material obtained on January 13, 2022 from https: //phys.org/news/2022-01-physicists-secret-sauce-exotic-properties.html (January 13, 2022) Discover the “secret source” behind the exotic traits of (Sun)

This document is subject to copyright. No part may be reproduced without written permission, except for fair transactions for personal investigation or research purposes. Content is provided for informational purposes only.

Physicists discover the “secret source” behind the exotic properties of new quantum materials

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Coroner Spotlights Domestic Violence, Homelessness, Fentanyl Crises in Annual Report

Taylor Johnston

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More than a third of the 61 people murdered in El Paso County last year were killed during a domestic or family violence situation.

Seven homeless people froze to death on the streets of Colorado Springs last year, and another five died from exposure to the elements from Jan. 1 through May 31 of this year.

And while youth suicides declined dramatically last year, more adolescents as well as adults are unintentionally dying from fentanyl, according to the 2021 El Paso County Coroner’s annual investigative-deaths report, released Tuesday.

“As our population grows, we’d expect to see all categories increase incrementally, but there are areas where we’ve left that trajectory,” said Dr. Leon Kelly, El Paso County coroner and chief medical examiner.

Fentanyl, a prescription pain drug, constitutes a “gross deviation” from predicted increases, Kelly said, largely because the synthetic opioid has wormed its way into many illicit street pills and often is ingested unknowingly.

That’s evidenced by the number of fentanyl-related deaths doubling for each of the past five years, he said.

Last year’s five accidental fentanyl-related deaths among children younger than age 18 surpassed the number of teen suicides last year, which fell from a record-tying high of 15 deaths in 2020 to only four deaths in 2021, statistics show.

“The big tipping point came when fentanyl went from an illegally trafficked drug to being stamped and masked as other medications,” Kelly said. “It’s easily carried, sold to kids in pills, and the cost has gone down because of the massive supply, so the barrier has been broken.”

Across the board, accidental drug-related deaths increased by 22% last year, with 107 methamphetamine deaths and 99 fentanyl deaths. Fentanyl also was found in a quarter of the meth overdoses.

Other trends that emerged from 2021 autopsied deaths:

o El Paso County saw a large increase in total firearms-related fatalities, jumping from 133 in 2020 to 167 last year.

o Homicides increased from 55 in 2020 to 61 in 2021, six of which occurred in a single mass-shooting event at a family gathering on Mother’s Day last year.

o The average age of the 78 people who died while homeless was 49 years old. Deaths of homeless during the first five months of this year are outpacing last year, with 48 deaths through through May 31.

o At least one military veteran or active-duty service member died by suicide every week in El Paso County last year.

o 58 people died in motor vehicle accidents, a decrease from 78 in 2020.

o However, 20 pedestrians and five bicyclists were killed in 2021, compared with 13 pedestrians and seven bicyclists in 2020.

o There were an additional 96 accidental deaths due to falls predominantly among the elderly, with an average age of 78.6 years, which were investigated without autopsy.

o 398 people died of natural causes, with cardiovascular disease as the top reason, causing 170 deaths, and chronic alcoholism attributed to 64 deaths.

The same type of prevention work that El Paso County has poured into reducing teen suicides needs to be deployed to counter the use of fentanyl, Kelly said.

Efforts are underway, he said, with the 4th Judicial District Attorney’s Office convening community leaders and experts to study lessons learned from youth suicide prevention that can be applied in attacking the newest threat to children’s lives.

Success in lessening youth suicides came because representatives from all sectors became part of a concerted push, Kelly said, after El Paso County ranked highest in the state and near the top in the nation for self-inflicted fatalities.

“Every conceivable youth-facing organization, from faith-based, to Inside Out (a lesbian, gay, bisexual and transgender organization that serves youth), to schools, to parents to law enforcement to mental health professionals identifying what was going on and what they could bring to the table,” Kelly said.

Face It Together, a nonprofit that provides peer coaching for adults with addictions and support for families, has seen “a great need” and an increase in people seeking help with opioid addiction such as fentanyl, said CEO Wendy White.

The organization opened its first Colorado office last April in Colorado Springs and also offers remote services nationwide.

“The power of using peers helps remove the shame and stigma, and breaks down barriers, allowing people to share their situation and add more tools to their toolbox,” White said.

She said she’d like to see a “harm-reduction” approach with test strips provided for drug users to determine the toxicity level of pills they might ingest.

The public now can buy Narcan, an antidote for people overdosing on opioids, at pharmacies without a prescription, said Dr. Eric Stein Bronsky, an emergency medicine physician with Penrose-St. Francis Health Services in Colorado Springs. Emergency medical technicians and police also carry doses, which is easily administered in a nasal spray, he said.

Also, hospitals dispense Narcan when discharging patients who are on pain medication, Bronsky said.

“Not all opiate doses are illegal; a tremendous amount of overdoses come from prescribed medication, and Grandma or Mom or Dad stacking pain medicine, or their body having a harsher response that can send them into respiratory decline,” he said.

Because fentanyl is hidden in pain pills that look like OxyContin or Percocet, for example, and is more potent than other drugs, opiate abuse won’t abate, Bronsky believes, until it’s seen as a health care crisis and not a legal problem.

“They can arrest more dealers, put more people in jail, but until we’re willing to concentrate on what it is — a health care crisis — people won’t be willing to solve it,” he said. “People are willing to solve a health care crisis.”


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Defense Contractor With 200-person Office in Colorado Springs Approves Company Merger

Taylor Johnston

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Vectrus shareholders approved a merger with The Vertex Co. to create the new military powerhouse, V2X, a $3.4 billion revenue company to be based out of northern Virginia, Vectrus announced in a news release Wednesday.

The transaction will give Vertex shareholders nearly two-thirds ownership of the company and Vectrus shareholders one third, creating one of the nation’s 20 largest defense contractors with 14,000 employees in 300 locations worldwide.

“Today’s (Wednesday’s) overwhelming approval marks a significant step toward completing our merger with Vertex, and creating one of the leading providers of critical mission solutions and support to defense clients globally,” Chief Executive Officer of Vectrus Chuck Prow said in the release. “Vectrus and Vertex — together as V2X — will be better positioned to meet the mission-essential needs of our clients while delivering cost efficiencies, increased security and resiliency, with more strategic use of resources.”

The melding of the two companies is likely save about $20 million a year by eliminating duplicated information technology, computer networks along with “some consolidation of people,” as V2X tries to tackles a contract backlog of more than $11 billion reaching into 2027.

Vectrus’ Colorado Springs office of 200 employees that focuses on sales, finance and human resources will stay in place, Vectrus Vice President Michael Smith confirmed.

Vertex also operates an office near the Colorado Springs Airport that supports a contract the company manages at a radar station in Alaska that feeds data to the North American Aerospace Defense Command (NORAD).

Summer jobs help area youths earn cash, develop skills

Prow will become CEO, Vectrus Chief Financial Officer Susan Lynch will hold the same post in the combined company and Vectrus board members will hold six of the 11 seats on the combined board, including the chairman’s post. Vertex CEO Ed Boyington will serve on the board and remain with the combined company until retiring after an unspecified transition period.

Vectrus, which specializes in logistics, information technology maintenance and operating military bases, is slightly larger than Vertex.

Vectrus generates about $190 million more in revenue and employs 2,400 more people, mostly at military bases around the world. Vertex specializes in aircraft maintenance, systems engineering and training.

“We thank all of our stakeholders for their continued support and look forward to completing the pending combination so we can begin unlocking the incredible potential of our combined platform,” Prow said.


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Wildlife Officials Warn of Possible Increase in Bear Encounters This Year

Taylor Johnston

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Colorado Parks and Wildlife is warning the public of the possibility of increased bear encounters this summer and fall because of late season storms that struck Colorado in May.

Bears’ diets depend on what kinds of foods are seasonally available such as grasses, berries, fruits, nuts and plants. These food sources can be disrupted in years that are abnormally dry or when there is a late frost like this year, wildlife officials said.

“We certainly see a correlation between annual failures of natural bear food sources and years with higher human-bear conflict rates,” said Mark Vieira, the state’s carnivore and furbearer program manger. “When natural food sources are scarce, as the smart flexible eaters that bears are, they tend to spend more time near humans.”

Bear encounters last year were down 28% compared to the previous two years. But encounters are expected to rise because of concerns about the late freeze that could limit food sources.

Wildlife officials said a late freeze occurred in May 2017 and led to a high conflict year where 109 bruins were relocated and 190 others were euthanized.

Mountainous and foothill areas from western Douglas County to Larimer County have already reported areas with frost damage to crops, while other forages continue to recover from wildfires, such as the Cameron Peak fire in 2020 — the largest in the state’s history.

“We have such a large fire footprint that the damage is already done as far as worrying about the soft mass production,” Wildlife Officer Shane Craig said. “I’m sure there were pockets of natural forage that survived, but we have already skated on our luck to get us past 2021.”

Wildlife officers are concerned about the number of gamble oak crops that died during the late season freeze. The crop produces acorns that become a vital source of food for bears as they prepare for winter and are in hyperphagia where they consume 20,000 calories a day.

Wildlife officials said nearly all emerging gamble oak crops above 6,800 feet in western Douglas County died in the late season freeze, but chokecherries and plums survived.

“We’ll be okay for the short (term), but in the 7-8 years I’ve been in my district I’ve never seen an oak dieoff like this,” Wildlife Officer Melanie Kaknes said in a news release. “The bears will have to figure out something because they have to put on weight for the winter. This dieoff (is) going to be pushing bears down in elevation and likely into towns.”

In western Jefferson County and eastern Park County, officials are concerned about the status of higher elevation crops.

“It is too early for me to know how things will pan out for the higher elevation stuff,” Wildlife Officer Dawson Swanson said in a news release. “On the good side we are getting some moisture that we desperately need, let’s just hope things did not freeze up high.”

Most adult bears survive year-to-year even if there is poor food availability.

Wildlife officials reminded residents and visitors to be aware of their surroundings and follow proper guidelines on living appropriately with bears.

These guidelines include:

Keep garbage in a well-secured enclosure.Only put out garbage on the morning of pickup; bring empty cans inside before dark.Use a bear-resistant trash can or dumpster. These are available online or from your trash hauler.Clean all garbage cans regularly to keep them odor free. The scent of ammonia can also deter bears.Take down all bird feeders. Bird feeders are a major contributor to bear/human conflicts and resulted in 1,073 conflicts between 2019 and 2021. Don’t leave pet food or stock feed outside.Install and test electric fencing to protect chicken coops, bee hives and livestock enclosuresKeep garage doors and windows closed and locked

For additional information about bears and guidance, click here.


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