Correlated Electrons “Tango” in a Perovskite Oxide at the Extreme Quantum Limit
Originally published by Oak Ridge National Laboratory.
A team led by the Department of Energy’s Oak Ridge National Laboratory has found a rare quantum material in which electrons move in coordinated ways, essentially “dancing.” Straining the material creates an electronic band structure that sets the stage for exotic, more tightly correlated behavior — akin to tangoing — among Dirac electrons, which are especially mobile electric charge carriers that may someday enable faster transistors. The results are published in the journal Science Advances.
“We combined correlation and topology in one system,” said co-principal investigator Jong Mok Ok, who conceived the study with principal investigator Ho Nyung Lee of ORNL. Topology probes properties that are preserved even when a geometric object undergoes deformation, such as when it is stretched or squeezed. “The research could prove indispensable for future information and computing technologies,” added Ok, a former ORNL postdoctoral fellow.
In conventional materials, electrons move predictably (for example, lethargically in insulators or energetically in metals). In quantum materials in which electrons strongly interact with each other, physical forces cause the electrons to behave in unexpected but correlated ways; one electron’s movement forces nearby electrons to respond.
To study this tight tango in topological quantum materials, Ok led the synthesis of an extremely stable crystalline thin film of a transition metal oxide. He and colleagues made the film using pulsed-laser epitaxy and strained it to compress the layers and stabilize a phase that does not exist in the bulk crystal. The scientists were the first to stabilize this phase.
Using theory-based simulations, co-principal investigator Narayan Mohanta, a former ORNL postdoctoral fellow, predicted the band structure of the strained material. “In the strained environment, the compound that we investigated, strontium niobate, a perovskite oxide, changes its structure, creating a special symmetry with a new electron band structure,” Mohanta said.
Different states of a quantum mechanical system are called “degenerate” if they have the same energy value upon measurement. Electrons are equally likely to fill each degenerate state. In this case, the special symmetry results in four states occurring in a single energy level.
“Because of the special symmetry, the degeneracy is protected,” Mohanta said. “The Dirac electron dispersion that we found here is new in a material.” He performed calculations with Satoshi Okamoto, who developed a model for discovering how crystal symmetry influences band structure.
“Think of a quantum material under a magnetic field as a 10-story building with residents on each floor,” Ok posited. “Each floor is a defined, quantized energy level. Increasing the field strength is akin to pulling a fire alarm that drives all the residents down to the ground floor to meet at a safe place. In reality, it drives all the Dirac electrons to a ground energy level called the extreme quantum limit.”
Lee added, “Confined here, the electrons crowd together. Their interactions increase dramatically, and their behavior becomes interconnected and complicated.” This correlated electron behavior, a departure from a single-particle picture, sets the stage for unexpected behavior, such as electron entanglement. In entanglement, a state Einstein called “spooky action at a distance,” multiple objects behave as one. It is key to realizing quantum computing.
“Our goal is to understand what will happen when electrons enter the extreme quantum limit, where we find phenomena we still don’t understand,” Lee said. “This is a mysterious area.”
Speedy Dirac electrons hold promise in materials including graphene, topological insulators and certain unconventional superconductors. ORNL’s unique material is a Dirac semimetal, in which electron valence and conduction bands cross and this topology yields surprising behavior. Ok led measurements of the Dirac semimetal’s strong electron correlations.
“We found the highest electron mobility in oxide-based systems,” Ok said. “This is the first oxide-based Dirac material reaching the extreme quantum limit.”
That bodes well for advanced electronics. Theory predicts that it should take about 100,000 tesla (a unit of magnetic measurement) for electrons in conventional semiconductors to reach the extreme quantum limit. The researchers took their strain-engineered topological quantum material to Eun Sang Choi of the National High Magnetic Field Laboratory at the University of Florida to see what it would take to drive electrons to the extreme quantum limit. There, he measured quantum oscillations showing the material would require only 3 tesla to achieve that.
Other specialized facilities allowed the scientists to experimentally confirm the behavior Mohanta predicted. The experiments occurred at low temperatures so that electrons could move around without getting bumped by atomic-lattice vibrations. Jeremy Levy’s group at the University of Pittsburgh and the Pittsburgh Quantum Institute confirmed quantum transport properties. With synchrotron x-ray diffraction, Hua Zhou at the Advanced Photon Source, a DOE Office of Science user facility at Argonne National Laboratory, confirmed that the material’s crystallographic structure stabilized in the thin film phase yielded the unique Dirac band structure. Sangmoon Yoon and Andrew Lupini, both of ORNL, conducted scanning transmission electron microscopy experiments at ORNL that showed that the epitaxially grown thin films had sharp interfaces between layers and that the transport behaviors were intrinsic to strained strontium niobate.
“Until now, we could not fully explore the physics of the extreme quantum limit due to the difficulties in pushing all electrons to one energy level to see what would happen,” Lee said. “Now, we can push all the electrons to this extreme quantum limit by applying only a few tesla of magnetic field in a lab, accelerating our understanding of quantum entanglement.”
The title of the Science Advances paper is “Correlated Oxide Dirac Semimetal in the Extreme Quantum Limit.”
The DOE Office of Science supported the research. High magnetic field measurements were performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation and the state of Florida. The research used resources of the Advanced Photon Source, a DOE Office of Science user facility at Argonne National Laboratory; its extraordinary facility operations to provide beam time during the pandemic were supported in part by the DOE Office of Science through the National Virtual Biotechnology Laboratory, a consortium of DOE national laboratories focused on the response to COVID-19, with funding provided by the Coronavirus CARES Act.
UT-Battelle manages ORNL for the Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.
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Fossil fuels just hit a record low in the US electricity mix last month, while solar and wind soared to all-time highs, according to fresh data from global energy think tank Ember.
In March 2025, fossil fuels accounted for less than 50% – 49.2% – of electricity generated for the first month on record. This beats the previous monthly record low of 51% set in April 2024.
“This clearly demonstrates the growing role of wind and solar in the US energy system,” said Nicolas Fulghum, senior analyst at global energy think tank Ember. “This is a first signal that the US is approaching a tipping point where clean power takes the lead over fossil generation, and where the importance of coal and gas inevitably starts to fade.”
What this means is that clean energy generated more than half – 50.8% – of US electricity for the first month on record. The record was driven by a surge in wind and solar power, which hit a new high of 24.4% of US electricity in March 2025.
In March 2025, US solar increased an astonishing 37% (+8.3 TWh) compared to March 2024. Wind increased by 12% (+5.7 TWh). Together, wind and solar reached an all-time high, generating 83 TWh of US electricity, 11% higher than the previous record of 75 TWh set in April 2024. Fossil fuel generation fell by 2.5% (-4.3 TWh) compared to March 2024.
The milestone is the result of a long-term decline of fossil generation in the US power sector, with wind and solar growing substantially over the last decade. In March 2015, fossil generation still provided 65% of US electricity generation. Wind and solar generation stood at just 5.7%. Since then, the share of wind and solar power has more than quadrupled.
“Wind and solar power are pushing fossil fuels out of the mix,” said Fulghum. “The reality on the ground is not one of a return to fossil fuels in the US, it’s the continued growth of solar and wind power that will be the dominant driver of electricity generation growth in the US.”
Solar power is set to account for more than half of new generating capacity installed in the US in 2025, with more than a third of new solar panels going to Texas. Solar adoption has exploded in just a decade. In March 2015, solar power accounted for just 1% of US electricity generation. By March 2025, it’s grown to 9.2%.
Last month, Ember published the report “US Electricity 2025,” which covered changes and trends in the US power sector in 2024. Solar was the fastest and largest growing source of electricity in the US in 2024. Wind and solar combined rose to a record 17% of the US electricity mix in 2024, overtaking coal for the first time, which accounted for 15%.
Read more: Made-in-America solar just got a big win in Louisiana
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Lease deals get all the hype, but most people still want to own the car after they’re done making all those payments on it. If that sounds like you, and you’ve been waiting for the interest rates on auto loans to drop, you’re in luck: there are a bunch of great plug-in cars you can buy with 0% financing and at pre-tariff prices this April!
As I was putting this list together, I realized there were plenty of ways for me to present this information. “Best EVs ..?” Too opinion based. “Cheapest EVs ..?” Too much research. “Best deal ..?” That’s usually subjective, but as automakers and dealers rush to raise prices in anticipation of Trump’s tariffs, two brands – Ford and Nissan – stand apart.
In the end, I went with alphabetical order, by make, so you’ll find out more about Ford and Nissan’s approach to the new market reality when you get to them. And, as for which deals are new this month? You’re just gonna have to read the article. Enjoy!
Acura ZDX
Manufactured in Spring Hill, Tennessee, the 2024 Acura ZDX uses a GM Ultium battery and drive motors, but the styling, interior, and infotainment software are all Honda. That means you’ll get a solidly-built EV with GM levels of parts support and Honda levels of fit, finish, and quality control. All that plus Apple CarPlay and (through April 30th) 0% financing for up to 72 months makes the ZDX one the best sporty crossover values in the business.
Chevy Blazer, Equinox EVs
Both the Chevy Blazer EV and Equinox EV are manufactured at GM’s Ramos Arizpe plant in Coahuila, Mexico, and each offers their own takes on the five-passenger family SUV. Despite any incoming tariffs, the crossovers you’ll find on dealer lots today still represent a solid value, with the cost of base model Equinox LT FWD models with 319 miles of EPA-rated range dropping to just $27,500 after you apply the $7,500 Federal tax credit (for now, still a thing).
Chrysler Pacifica PHEV
When the plug-in hybrid version of the Chrysler Pacifica minivan first went on sale all the way back in 2016, it seemed to imply that the old Chrysler Corporation was going to race ahead of the other Big Three US carmakers.
That didn’t happen, but the Pacifica is still the king of cupholders, while the van’s stow n’ go seating, and all the other practical, clever details that add up to remind you Chrysler invented these things – and through April 30th, you can get 0% financing for up to 72 months on 2025 MY examples of this made-in-Canada plug-in hybrid and cover up to 32 miles of your daily driving needs on the clean, pure power of electrons.
Ford Mustang Mach-E
As I mentioned at the top of the article, both Ford and Nissan have taken steps to push back against the Trump tariffs – and in Ford’s case, that means big discounts, employee pricing for all, and free chargers for EV buyers.
In addition to employee pricing, 2024 Mustang Mach-Es continue to offer 0% APR financing for up to 72 months. That offer appears to be stackable with $2,500 in bonus cash, too, and Tesla owners and lessees can also score $1,000 in conquest cash for up to $3,500 off.
GMC HUMMER EV
The biggest of the Ultium-based EVs, these Hamtramck, Michigan-built machines are seriously impressive EVs, with shockingly quick acceleration and on-road handling that seems to defy the laws of physics once you understand that these are, essentially, medium-duty trucks. If you’re a fan of heavy metal (and plastic), you’ll definitely want to stop by your local GMC dealer and give the rugged GMC HUMMER EV a test drive.
Honda Prologue
Manufactured alongside its GM siblings at the Ramos Arizpe plant in Coahuila, Mexico, the hot-selling Honda Prologue pairs GM’s excellent Ultium platform with Honda sensibilities and Apple CarPlay to create a winning combination.
If you’ve been holding off, we’ve got good news: there’s still a few remaining 2024 models in dealer inventory out there. To make room for the 2025 models, Honda is offering 0% APR for up to 72 months on the remaining 2024s.
Click here to find a 0% interest (72 mo.) deal on a 2024 Prologue near you.
Hyundai IONIQ 6
The ultra-efficient Hyundai IONIQ 6 is one of the most compelling Model 3 competitors out there – but that could change if the Korean-built sedan gets hit with heavy tariffs. To make sure that doesn’t happen, Hyundai is investing tens of billions of dollars into a US manufacturing base, creating new American jobs and ensuring (kinda) that it can continue to deliver real value to its customers.
The fast-charging IONIQ 6 offers up to 342 miles of range on its most efficient version, while even the shortest range models offer 220 miles of range. Through April 30th, Hyundai is offering a rare 0% interest deal on remaining 2024 examples of its slippery sedan for up to 48 months.
All the Kia EVs
Kia has something for just about everyone in its EV range, from the fun, compact, and underrated Niro EV to the practical three-row EV9 to the supercar-baiting performance of the Kia EV6 – a car that made its global debut on a drag strip running alongside a Lamborghini, a Porsche, and an AMG Mercedes GT.
Through April 30th, you can get 0% interest on just about every new EV you’ll find on your Kia dealer’s lot (minus 2025 Kia EV6 models). Click the links below to find yours.
Mitsubishi Outlander PHEV
One of the first three-row plugin cars to hit the market, Mitsubishi’s Outlander PHEV has always presented a strong value proposition with up to 38 miles of electric range from its 20 kWh li-ion battery and room for seven (in a pinch), making it a great “lily pad” vehicle for suburban families who want to drive electric but still worry about being able to find a charging station when they need one.
That might change when the tariffs take full effect, however – so if you’re looking for an affordable 7-passenger plug-in with a great safety rating at a reasonably affordable price, act fast.
Nissan Ariya
I’ve already said that the Nissan Ariya didn’t get a fair shake. If you click that link, you’ll read about a car that offers solid driving dynamics, innovative interior design, and all the practicality that makes five-passenger crossovers the must-haves they’ve become for most families. Now, Nissan is slashing prices across the line as their competitors are raising theirs, making the case for the Ariya even stronger than before.
With great discounts available at participating dealers, Supercharger access, and 0% interest from Nissan for up to 72 months on both 2024 and 25 MY Ariya EVs.
Toyota bZ4X
Built in Toyota City, Japan, the bZ4X EV is a capable, dependable crossover with room for five and Toyota’s reputation for reliability and longevity to boot. With 0% financing and big discounts on both 2024 and 2025 models, the bZ4X might be the best deal on your local Toyota dealer’s lot.
Volkswagen ID.4
One of the most popular legacy EVs, the ID.4 offers Volkswagen build quality and (for 2024) a Chat-GPT enabled interface. To keep ID.4 sales rolling, VW dealers are getting aggressive with discounts, making this fast-charging, 291 mile EPA-rated range, 5-star safety rated EV a value proposition that’s tough to beat.
This month, get a Volkswagen ID.4 fresh from the company’s Chattanooga, Tennessee assembly plant with 0% financing for up to 72 months plus a $5,000 customer cash bonus on remaining 2024 models to stack with it.
Disclaimer: the vehicle models and financing deals above were sourced from CarsDirect, CarEdge, CarFax, USNews, and (where mentioned) the OEM websites – and were current as of 03APR2025. These deals may not be available in every market, with every discount, or for every buyer (the standard “with approved credit” fine print should be considered implied). Check with your local dealer(s) for more information.
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Environment
Why OPEC+ is accelerating oil production as prices are tanking and tariffs hammer markets
The Phillips 66 Company’s Los Angeles Refinery in California.
Bing Guan | Reuters
The oil price outlook is being hit with more bearish forecasts on the back of U.S. President Donald Trump’s sweeping and market-hammering tariff announcements. Businesses and investors worry that a trade war and lower global growth lies ahead.
Goldman Sachs on Thursday reduced its December 2025 forecasts for global and U.S. benchmarks Brent crude and WTI by $5 to $66 and $62 a barrel, respectively, “because the two key downside risks we have flagged are realizing, namely tariff escalation and somewhat higher OPEC+ supply.”
The bank also cut its forecasts for the oil benchmarks in 2025 and 2026, adding that “we no longer forecast a price range, because price volatility is likely to stay elevated on higher recession risk.” Analysts at S&P Global Market Intelligence predict that in a worst-case scenario, global oil demand growth could be slashed by 500,000 barrels per day.
JPMorgan, for its part, raised its recession odds for the global economy to 60% for this year, up from a previous forecast of 40%.
Markets were therefore stunned when OPEC, which produces about 40% of the world’s crude oil — along with its non-OPEC allies that together comprise OPEC+ — chose not only to go ahead with its previously held plans to increase oil production, but also to nearly triple the expected increase figure.
Eight key OPEC+ producers on Thursday agreed to raise combined crude oil output by 411,000 barrels per day, speeding up the pace of their scheduled hikes and pushing down oil prices. The group — Saudi Arabia, Russia, Iraq, the United Arab Emirates, Kuwait, Kazakhstan, Algeria, and Oman — was widely expected to implement an increase of just under 140,000 barrels per day next month.
The news pushed oil prices 6% lower.
OPEC+ bullishness and appeasing Trump
Several factors underpin the oil-producing alliance’s decision. One is that the group is bullish on oil demand later in the year, putting it firmly in the minority as investor outlooks sour and fears of a global slowdown worsen.
The eight OPEC+ members behind the production decision cited “the continuing healthy market fundamentals and the positive market outlook” in their statement Thursday, saying that “this measure will provide an opportunity for the participating countries to accelerate their compensation.”
The statement added that “the gradual increases may be paused or reversed subject to evolving market conditions.”
Another likely reason for the group’s move has to do with another T-word: the man in the White House, who during his first term in office and from the very start of his second, has loudly demanded that the oil producer group pump more crude to help bring down prices for Americans.
“First of all, this is partly about appeasing Trump,” Saul Kavonic, head of energy research at MST Marquee, told CNBC’s Dan Murphy on Friday.
“Trump will be putting pressure on OPEC to reduce oil prices, which reduces global energy prices, to help offset the inflationary impact of his tariffs.”
OPEC officials have denied that the move was made to appease Trump.
Compliance and market share
Meanwhile, as compliance is a major issue for OPEC+ — with countries overproducing crude beyond their quotas, complicating the group’s efforts to control how much supply it allows into the market — the move could be a way to enforce that, according to Helima Croft, head of global commodity strategy and MENA research at RBC Capital Markets.
“We think a desire by the OPEC leadership to send a warning signal to Kazakhstan, Iraq, and even Russia about the cost of continued overproduction underlies the decision.”
Helima Croft
head of global commodity strategy and MENA research at RBC Capital Markets
“We think a desire by the OPEC leadership to send a warning signal to Kazakhstan, Iraq, and even Russia about the cost of continued overproduction underlies the decision,” Croft wrote in a note published Thursday. She referenced the March 2020 oil price war, when Saudi Arabia flooded the market with supply to tank oil prices and forced Russia back into compliance after Moscow initially refused to curb production to help the alliance stabilize prices. The price war caused Brent crude prices to go as low as $15 a barrel.
The production increases are also “an example of OPEC increasing their market share,” Kavonic said, adding that it “ultimately does come at the expense of the United States [shale] patch,” which U.S. producers likely will not be too thrilled about.
What happens next?
OPEC+ appears confident about the market turning a corner in the coming months on the assumption that oil demand will increase in the summer and the tariff wars will be resolved in the coming months, said Nader Itayim, editorial manager at Argus Media.
“These countries are largely comfortable with the $70, $75 per barrel band,” Itayim said.
What comes next depends on the trajectory of the tariffs and a potential trade war. Oil dropping into the $60 range could force pauses or even a reversal in OPEC+ production increase plans, analysts say – although that is likely to be met with resistance from countries like Iraq and Kazakhstan that have long been itching to increase their oil production for their own revenues.
Whatever happens, the group maintains the flexibility to adapt its plans month by month, Itayim noted.
“If things don’t quite go the way they imagine, all it does take, really, is a phone call.”
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