-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Hole Truth: Via Integrity in an HDI World
From the drilled hole to registration across multiple sequential lamination cycles, to the quality of your copper plating, via reliability in an HDI world is becoming an ever-greater challenge. This month we look at “The Hole Truth,” from creating the “perfect” via to how you can assure via quality and reliability, the first time, every time.
In Pursuit of Perfection: Defect Reduction
For bare PCB board fabrication, defect reduction is a critical aspect of a company's bottom line profitability. In this issue, we examine how imaging, etching, and plating processes can provide information and insight into reducing defects and increasing yields.
Voices of the Industry
We take the pulse of the PCB industry by sharing insights from leading fabricators and suppliers in this month's issue. We've gathered their thoughts on the new U.S. administration, spending, the war in Ukraine, and their most pressing needs. It’s an eye-opening and enlightening look behind the curtain.
- Articles
- Columns
- Links
- Media kit
||| MENU - pcb007 Magazine
Breaking Electron Waves Provide New Clues to High-Temperature Superconductivity
December 7, 2017 | Brookhaven National LaboratoryEstimated reading time: 4 minutes

Superconductors carry electricity with perfect efficiency, unlike the inevitable waste inherent in traditional conductors like copper. But that perfection comes at the price of extreme cold—even so-called high-temperature superconductivity (HTS) only emerges well below zero degrees Fahrenheit. Discovering the ever-elusive mechanism behind HTS could revolutionize everything from regional power grids to wind turbines.
Image caption: In the RIXS technique, intense x-rays deposit energy into the electron waves of atomically thin layers of high-temperature superconductors. The difference in x-ray energy before and after interaction reveals key information about the fundamental behavior of these exciting and mysterious materials.
Now, a collaboration led by the U.S. Department of Energy’s Brookhaven National Laboratory has discovered a surprising breakdown in the electron interactions that may underpin HTS. The scientists found that as superconductivity vanishes at higher temperatures, powerful waves of electrons begin to curiously uncouple and behave independently—like ocean waves splitting and rippling in different directions.
“For the first time, we pinpointed these key electron interactions happening after superconductivity subsides,” said first author and Brookhaven Lab research associate Hu Miao. “The portrait is both stranger and more exciting than we expected, and it offers new ways to understand and potentially exploit these remarkable materials.”
Brookhaven's Robert Konik, Genda Gu, Mark Dean, and Hu Miao
The new study, published November 7 in the journal PNAS, explores the puzzling interplay between two key quantum properties of electrons: spin and charge.
“We know charge and spin lock together and form waves in copper-oxides cooled down to superconducting temperatures,” said study senior author and Brookhaven Lab physicist Mark Dean. “But we didn’t realize that these electron waves persist but seem to uncouple at higher temperatures.”
Electronic stripes and waves
Scientists at Brookhaven Lab discovered in 1995 that spin and charge can lock together and form spatially modulated “stripes” at low temperatures in some HTS materials. Other materials, however, feature correlated electron charges rolling through as charge-density waves that appear to ignore spin entirely. Deepening the HTS mystery, charge and spin can also abandon independence and link together.
“The role of these ‘stripes’ and correlated waves in high-temperature superconductivity is hotly debated,” Miao said. “Some elements may be essential or just a small piece of the larger puzzle. We needed a clearer picture of electron activity across temperatures, particularly the fleeting signals at warmer temperatures.”
Imagine knowing the precise chemical structure of ice, for example, but having no idea what happens as it transforms into liquid or vapor. With these copper-oxide superconductors, or cuprates, there is comparable mystery, but hidden within much more complex materials. Still, the scientists essentially needed to take a freezing-cold sample and meticulously warm it to track exactly how its properties change.
Subtle signals in custom-made materials
The team turned to a well-established HTS material, lanthanum-barium copper-oxides (LBCO) known for strong stripe formations. Brookhaven Lab scientist Genda Gu painstakingly prepared the samples and customized the electron configurations.
“We can’t have any structural abnormalities or errant atoms in these cuprates—they must be perfect,” Dean said. “Genda is among the best in the world at creating these materials, and we’re fortunate to have his talent so close at hand.”
At low temperatures, the electron signals are powerful and easily detected, which is part of why their discovery happened decades ago. To tease out the more elusive signals at higher temperatures, the team needed unprecedented sensitivity.
“We turned to the European Synchrotron Radiation Facility (ESRF) in France for the key experimental work,” Miao said. “Our colleagues operate a beamline that carefully tunes the x-ray energy to resonate with specific electrons and detect tiny changes in their behavior.”
The team used a technique called resonant inelastic x-ray scattering (RIXS) to track position and charge of the electrons. A focused beam of x-rays strikes the material, deposits some energy, and then bounces off into detectors. Those scattered x-rays carry the signature of the electrons they hit along the way.
As the temperature rose in the samples, causing superconductivity to fade, the coupled waves of charge and spin began to unlock and move independently.
“This indicates that their coupling may bolster the stripe formation, or through some unknown mechanism empower high-temperature superconductivity,” Miao said. “It certainly warrants further exploration across other materials to see how prevalent this phenomenon is. It’s a key insight, certainly, but it’s too soon to say how it may unlock the HTS mechanism.”
That further exploration will include additional HTS materials as well as other synchrotron facilities, notably Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II), a DOE Office of Science User Facility.
“Using new beamlines at NSLS-II, we will have the freedom to rotate the sample and take advantage of significantly better energy resolution,” Dean said. “This will give us a more complete picture of electron correlations throughout the sample. There’s much more discovery to come.”
Additional collaborators on the study include Yingying Peng, Giacomo Ghiringhelli, and Lucio Braicovich of the Politecnico di Milano, who contributed to the x-ray scattering, as well as José Lorenzana of the University of Rome, Götz Seibold of the Institute for Physics in Cottbus, Germany, and Robert Konik of Brookhaven Lab, who all contributed to the theory work.
This research was funded by DOE’s Office of Science through Brookhaven Lab’s Center for Emergent Superconductivity.
Suggested Items
Copper Price Surge Raises Alarms for Electronics
07/15/2025 | Global Electronics Association Advocacy and Government Relations TeamThe copper market is experiencing major turbulence in the wake of U.S. President Donald Trump’s announcement of a 50% tariff on imported copper effective Aug. 1. Recent news reports, including from the New York Times, sent U.S. copper futures soaring to record highs, climbing nearly 13% in a single day as manufacturers braced for supply shocks and surging costs.
I-Connect007 Editor’s Choice: Five Must-Reads for the Week
07/11/2025 | Andy Shaughnessy, Design007 MagazineThis week, we have quite a variety of news items and articles for you. News continues to stream out of Washington, D.C., with tariffs rearing their controversial head again. Because these tariffs are targeted at overseas copper manufacturers, this news has a direct effect on our industry.I-Connect007 Editor’s Choice: Five Must-Reads for the Week
Digital Twin Concept in Copper Electroplating Process Performance
07/11/2025 | Aga Franczak, Robrecht Belis, Elsyca N.V.PCB manufacturing involves transforming a design into a physical board while meeting specific requirements. Understanding these design specifications is crucial, as they directly impact the PCB's fabrication process, performance, and yield rate. One key design specification is copper thieving—the addition of “dummy” pads across the surface that are plated along with the features designed on the outer layers. The purpose of the process is to provide a uniform distribution of copper across the outer layers to make the plating current density and plating in the holes more uniform.
Trump Copper Tariffs Spark Concern
07/10/2025 | I-Connect007 Editorial TeamPresident Donald Trump stated on July 8 that he plans to impose a 50% tariff on copper imports, sparking concern in a global industry whose output is critical to electric vehicles, military hardware, semiconductors, and a wide range of consumer goods. According to Yahoo Finance, copper futures climbed over 2% following tariff confirmation.
Happy’s Tech Talk #40: Factors in PTH Reliability—Hole Voids
07/09/2025 | Happy Holden -- Column: Happy’s Tech TalkWhen we consider via reliability, the major contributing factors are typically processing deviations. These can be subtle and not always visible. One particularly insightful column was by Mike Carano, “Causes of Plating Voids, Pre-electroless Copper,” where he outlined some of the possible causes of hole defects for both plated through-hole (PTH) and blind vias.