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Contact: Brendan Lynch, KU News Service, 785-864-8855, [email protected], @BrendanMLynch

Ultrafast lasers map electrons ‘going ballistic’ in graphene, with implications for next-gen electronic devices

LAWRENCE — Research appearing in ACS Nano, a premier journal on nanoscience and nanotechnology, reveals the ballistic movement of electrons in graphene in real time.

The observations, made at the University of Kansas’ Ultrafast Laser Lab, could lead to breakthroughs in governing electrons in semiconductors, fundamental components in most information and energy technology.

“Generally, electron movement is interrupted by collisions with other particles in solids,” said lead author Ryan Scott, a doctoral student in KU’s Department of Physics & Astronomy. “This is similar to someone running in a ballroom full of dancers. These collisions are rather frequent — about 10 to 100 billion times per second. They slow down the electrons, cause energy loss and generate unwanted heat. Without collisions, an electron would move uninterrupted within a solid, similar to cars on a freeway or ballistic missiles through air. We refer to this as ‘ballistic transport.’”

Scott performed the lab experiments under the mentorship of Hui Zhao, professor of physics & astronomy at KU. They were joined in the work by former KU doctoral student Pavel Valencia-Acuna, now a postdoctoral researcher at the Northwest Pacific National Laboratory.

Zhao said electronic devices utilizing ballistic transport could potentially be faster, more powerful and more energy efficient.

“Current electronic devices, such as computers and phones, utilize silicon-based field-effect transistors,” Zhao said. “In such devices, electrons can only drift with a speed on the order of centimeters per second due to the frequent collisions they encounter. The ballistic transport of electrons in graphene can be utilized in devices with fast speed and low energy consumption.”

The KU researchers observed the ballistic movement in graphene, a promising material for next-generation electronic devices. First discovered in 2004 and awarded the Nobel Prize in Physics in 2010, graphene is made of a single layer of carbon atoms forming a hexagonal lattice structure — somewhat like a soccer net.

“Electrons in graphene move as if their ‘effective’ mass is zero, making them more likely to avoid collisions and move ballistically,” Scott said. “Previous electrical experiments, by studying electrical currents produced by voltages under various conditions, have revealed signs of ballistic transport. However, these techniques aren’t fast enough to trace the electrons as they move.”

According to the researchers, electrons in graphene (or any other semiconductor) are like students sitting in a full classroom, where students can’t freely move around because the desks are full. The laser light can free electrons to momentarily vacate a desk, or ‘hole’ as physicists call them.

“Light can provide energy to an electron to liberate it so that it can move freely,” Zhao said. “This is similar to allowing a student to stand up and walk away from their seat. However, unlike a charge-neutral student, an electron is negatively charged. Once the electron has left its ‘seat,’ the seat becomes positively charged and quickly drags the electron back, resulting in no more mobile electrons — like the student sitting back down.”

Because of this effect, the super-light electrons in graphene can only stay mobile for about one-trillionth of a second before falling back to its seat. This short time presents a severe challenge to observing the movement of the electrons. To address this problem, the KU researchers designed and fabricated a four-layer artificial structure with two graphene layers separated by two other single-layer materials, molybdenum disulphide and molybdenum diselenide.

“With this strategy, we were able to guide the electrons to one graphene layer while keeping their ‘seats’ in the other graphene layer,” Scott said. “Separating them with two layers of molecules, with a total thickness of just 1.5 nanometers, forces the electrons to stay mobile for about 50-trillionths of a second, long enough for the researchers, equipped with lasers as fast as 0.1 trillionth of a second, to study how they move.”

The researchers use a tightly focused laser spot to liberate some electrons in their sample. They trace these electrons by mapping out the “reflectance” of the sample, or the percentage of light they reflect.

“We see most objects because they reflect light to our eyes,” Scott said. “Brighter objects have larger reflectance. On the other hand, dark objects absorb light, which is why dark clothes become hot in the summer. When a mobile electron moves to a certain location of the sample, it makes that location slightly brighter by changing how electrons in that location interact with light. The effect is very small — even with everything optimized, one electron only changes the reflectance by 0.1 part per million.”

To detect such a small change, the researchers liberated 20,000 electrons at once, using a probe laser to reflect off the sample and measure this reflectance, repeating the process 80 million times for each data point. They found the electrons on average move ballistically for about 20-trillionths of a second with a speed of 22 kilometers per second before running into something that terminates their ballistic motion.

The research was funded by a grant from the Department of Energy under the program of Physical Behavior of Materials.

Zhao said currently his lab is working to refine their material design to guide electrons more efficiently to the desired graphene layer, and trying to find ways to make them move longer distances ballistically.

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KU News Service

1450 Jayhawk Blvd.

Lawrence KS 66045

Phone: 785-864-3256

Fax: 785-864-3339

[email protected]

http://www.news.ku.edu

Erinn Barcomb-Peterson, director of news and media relations, [email protected]

Today’s News is a free service from the Office of Public Affairs

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Survey finds chain store pharmacy employees dissatisfied with working conditions

LAWRENCE — A newly published survey from University of Kansas researchers reveals that chain store pharmacists and pharmacy technicians were dissatisfied with certain job conditions even before the COVID-19 pandemic increased their stress, and it sheds light on some of the strike actions they’ve undertaken this year. Researchers surveyed 129 pharmacists and 111 pharmacy technicians, asking them 92 questions about their work, including perceptions of their workplace autonomy, competence, relationships, pay satisfaction and benefit satisfaction.

Advantages of scheduling retail employees with higher performers revealed in new study

LAWRENCE — New research from the University of Kansas School of Business examines how sales employees’ social contexts — particularly their being co-scheduled with higher performers — relate to changes in performance over time. Results show co-scheduling with higher performers has an immediate negative effect but is positively associated with performance over time.

Full stories below.

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Contact: Rick Hellman, KU News Service, 785-864-8852, [email protected], @RickHellman

Survey finds chain store pharmacy employees dissatisfied with working conditions

LAWRENCE — A newly published survey reveals that chain store pharmacists and pharmacy technicians were dissatisfied with certain job conditions even before the COVID-19 pandemic increased their stress, and it sheds light on some of the strike actions they’ve undertaken this year.

The paper, “Pharmacy Work: Intrinsic Motivation and Extrinsic Rewards Across Role and Setting,” was just published in the Journal of the American Pharmacists Association. The co-authors are Angela Gist-Mackey and Cameron Piercy, both associate professors in the University of Kansas Department of Communication Studies, and Jessica Bates, clinical associate professor in the KU School of Pharmacy.

They surveyed 129 pharmacists and 111 pharmacy technicians, asking them 92 questions about their work, including perceptions of their workplace autonomy, competence, relationships, pay satisfaction and benefit satisfaction. The pharmacies in which they worked were categorized into one of three settings: chain store, independent or health care system.

The survey was conducted in 2020, just before COVID-19 pandemic lockdowns were declared across the country and around the world.

“Even before the pandemic, there were stressors in the community-retail sector: just feeling a little undervalued, staff hours constantly being cut, pharmacist overlap hours being cut and additional tasks being added to your workday,” Bates said. “Then with a pandemic and the introduction of a lot more vaccinations into your normal workflow, it really adds to the stress. Plus, people were leaving the health care workforce in general just because of the pandemic, and many had fears of what the illness might do to them personally.”

Bates said that not only have “lots more vaccinations been given, but the volume of regular prescriptions is continuing to increase as the population ages.”

For Gist-Mackey, “the more compelling finding” is the perception of pay and benefits by chain store workers.

“We asked our participants about their income, and that did not vary across context. But what was really interesting was that chain employees were largely dissatisfied with their compensation and pay, even though they’re being equitably compensated,” Gist-Mackey said. “So there is something happening in chain store workplace contexts. … I would argue it’s likely they feel they’re just not being compensated enough to deal with the kinds of things chain pharmacy employees are having to deal with at work. It doesn’t seem worth it.”

These findings of relative satisfaction — with both pay and other conditions — were consistent within pharmacy setting, applying to both pharmacists and lower-paid pharmacy technicians.

“We expected, and hypothesized, that pharmacy technicians and the pharmacists would differ a lot,” Piercy said. “But what we found is the setting is the big driving force here. It’s not the role that you’re in.”

The KU researchers said they initially received some pushback from journal editors, concerned they had exaggerated the influence of the chain store setting in their study. But while in the review process, a series of strikes this fall by CVS and Walgreens pharmacists seemed to soften their objections, Gist-Mackey said.

“It helped us persuade the editorial team that we’re not exaggerating those findings around context, that where you’re working does matter, and that it is negatively affecting people’s work lives, so much so that they were willing to walk out to make a stand for better conditions,” Gist-Mackey said. “We’ll see if anything changes.”

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The official university Twitter account has changed to @UnivOfKansas.

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Contact: Jon Niccum, KU News Service, 785-864-7633, [email protected]

Advantages of scheduling retail employees with higher performers revealed in new study

LAWRENCE — One barely has to wade into a Reddit thread in which workers whine about their employer before encountering something related to shifts. This often focuses on with whom a worker is scheduled and how that makes things better or worse.

“Shift work is prevalent in most businesses, and yet it doesn’t really fit into any of our big pillars of HR research,” said Patrick Downes, associate professor of management & entrepreneurship at the University of Kansas School of Business.

That void in the literature led to his new article, “A Relational View of Shiftwork: Co-scheduling With Higher Performers.” It examines how sales employees’ social contexts — particularly their being co-scheduled with higher performers — relate to changes in performance over time. Results show co-scheduling with higher performers has an immediate negative effect but is positively associated with performance over time.

It’s published in Human Resource Management.

Co-written with KU doctoral candidate Ella Lee, the article finds that management often views shift work only from an operations perspective.

“They think, ‘If I’m going to have 1,000 customers, then I need 10 employees to service those 1,000 customers across a certain period of time. Therefore, we just need 10 bodies scheduled on Thursday,’” Downes said.

“Our point is that when you put those 10 people in there, now you’ve created all these social interactions — actually 45 possible pairs of social interactions. So how does that affect the business?”

The study determined that if a sales employee works one week with a higher performer, then the employee’s performance will initially be slightly worse. But in the following month, the employee’s performance goes up about 2% per week.

“So if you work a full month with someone better than you, then the next month you’re going to be almost 8% higher in terms of your sales,” Downes said.

Conversely, if the same employee works with a lower performer, the results do not decline.

“One of the reasons is you don’t learn from lower performers quite in the same way as higher performers. If someone is not as good, it’s not like you can learn something from them that can be put into practice,” he said.

This study applies primarily to sales-related jobs. More interdependent shift work where employees have to rely on each other – line cooks in a restaurant, for example – does not offer the same competitive component.

“Because if you’re really good, it’s not going to hurt me if we have to team up to serve this customer,” Downes said.

His theory was tested using archival records of a large U.S. consumer retail organization. Records included monthly sales metrics and shifts worked in a single year by 7,893 retail sales representatives.

“It’s a big dataset involving several hundred stores,” he said. “We looked at every shift that every employee co-worked with somebody else. Then we went back and looked at, ‘OK, this person was a better performer than you in the past, and you spent four hours with them on this day. So how did that predict your performance a month later?’”

Downes is currently in his third year at KU. He teaches topics in HR, and his research focuses on how employees’ social contexts affect their motivation. Human Resource Management awarded Downes and Lee the 2023 Best Article Award for their study.

If the professor suddenly found himself in charge of an HR department, how would he implement these findings?

“I think particularly at scale, one of the things happening now in organizations is a big push to use data to make people-related decisions. And this is a space where the big companies and medium-sized companies can do this,” Downes said.

“If you have a few hundred shift workers, it’s worth investing in some analytical models to decide who should be working with who, and when and where.”

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KU News Service

1450 Jayhawk Blvd.

Lawrence KS 66045

Phone: 785-864-3256

Fax: 785-864-3339

[email protected]

http://www.news.ku.edu

Erinn Barcomb-Peterson, director of news and media relations, [email protected]

Today’s News is a free service from the Office of Public Affairs

From the Office of Public Affairs | http://www.news.ku.edu

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Kansas Geological Survey, state agency to measure groundwater levels in western Kansas

LAWRENCE — A crew from the Kansas Geological Survey, based at the University of Kansas, along with staff from three field offices of the Kansas Department of Agriculture’s Division of Water Resources will be in western Kansas measuring groundwater levels in January 2024. Levels are measured annually as part of a joint project to monitor the health of the state’s valuable groundwater resources. Weather permitting, the KGS crew will be working near Colby on Jan. 2, Goodland on Jan. 3, Ulysses on Jan. 4, Liberal on Jan. 5 and Dodge City on Jan. 6. DWR staff will measure wells in other parts of the region. Results will be published in February 2024.

Dole Institute continues work on new NEH grant to expand online portal for congressional archives

LAWRENCE – In July, the Dole Institute of Politics at the University of Kansas began work to expand the American Congress Digital Archives Portal, along with partner institutions, as part of a nearly $350,000 grant from the National Endowment for the Humanities. The American Congress Digital Archives Portal provides open access to congressional archives by bringing together these civically important sources from multiple, geographically dispersed institutions using open-source software into a single online portal.

Full stories below.

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Contact: Brownie Wilson, Kansas Geological Survey, 785-864-2118, [email protected]

Kansas Geological Survey, state agency to measure groundwater levels in western Kansas

LAWRENCE — A crew from the Kansas Geological Survey, based at the University of Kansas, along with staff from three field offices of the Kansas Department of Agriculture’s Division of Water Resources will be in western Kansas measuring groundwater levels the first week of January 2024.

Levels are measured annually as part of a joint project to monitor the health of the state’s valuable groundwater resources.

Weather permitting, the KGS crew will be working near Colby on Jan. 2, Goodland on Jan. 3, Ulysses on Jan. 4, Liberal on Jan. 5 and Dodge City on Jan. 6. DWR staff will measure wells in other parts of the region.

Brownie Wilson, KGS water-data manager, expects this winter’s measurements to show a general decline in the water table, though not as steep as last year’s results.

“In several locations, 2022 was one of the driest years on record in Kansas, and those prevalent drought conditions carried over into the spring of 2023,” Wilson said. “Fortunately, much of western Kansas saw gentle and widespread rains throughout the early summer months. This allowed a lot of producers to shut down their wells and reduce the pumping stress on the aquifer, especially in the Ogallala region of the High Plains Aquifer in Kansas.”

The High Plains Aquifer underlies portions of eight states. In Kansas, it encompasses three individual aquifers — the Ogallala Aquifer in the western third of the state, the Equus Beds around Wichita and Hutchinson, and the Great Bend Prairie Aquifer around Pratt and Great Bend.

South-central Kansas may prove an exception to the expected measurement trends.

“They missed out on much of those rainfall events, and unfortunately the drought conditions have been hanging on throughout the summer and fall,” Wilson said.

Most of the wells measured by KGS and DWR tap into the High Plains Aquifer, a massive network of underground water-bearing rocks and the main source of water in western Kansas. The rest draw from deeper aquifers or shallower alluvial aquifers along creeks and rivers.

Groundwater levels in much of the state’s portion of the Ogallala Aquifer, especially in southwest Kansas, have been on the decline since water use started to rise in the mid-20th century. Dry years lead to increased water usage, primarily for irrigation, which in turn typically causes greater declines in water levels.

The KGS and DWR measure depth to water in more than 1,400 wells in 48 counties, primarily in January to avoid as much as possible skewed data associated with short-term declines caused by widespread pumping during the growing season. This year, KGS will measure 577 wells, and crews from the DWR’s field offices in Garden City, Stafford and Stockton will measure 835.

Wells are accessed with landowners’ permission, and many have been monitored for years, although new wells are added as older wells become inaccessible or to fill in spatial gaps in the monitoring network. The majority are within the boundaries of the state’s five groundwater management districts (GMDs), which are organized and governed by area landowners and water users to address local water-resource issues.

Historical annual measurements for each well are available on the KGS website. Results of measurements made in January will be added in late February 2024.

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The official university Twitter account has changed to @UnivOfKansas.

Refollow @KUNews for KU News Service stories, discoveries and experts.

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Contact: Maria Fisher, Dole Institute of Politics, 785-864-4900, [email protected]

Dole Institute continues work on new NEH grant to expand online portal for congressional archives

LAWRENCE – In July, the Dole Institute of Politics at the University of Kansas began work to expand the American Congress Digital Archives Portal, along with partner institutions, as part of a nearly $350,000 grant from the National Endowment for the Humanities.

The American Congress Digital Archives Portal provides open access to congressional archives by bringing together these civically important sources from multiple, geographically dispersed institutions using open-source software into a single online portal. The portal will illuminate connections across collections; provide opportunities for new scholarship, as well as civics and history education; and make the archives of the “People’s Branch” more equitably available to the people.

Other partner institutions on the project include West Virginia University Libraries, the Carl Albert Congressional Research and Studies Center at the University of Oklahoma, the Dirksen Congressional Center, the Richard B. Russell Library for Political Research and Studies at University of Georgia, and the University of Hawai`i Congressional Papers Collection. WVU Libraries is leading the project, which also includes an advisory board composed of leading individuals in the areas of congressional archives and scholarship.

“We are so excited to continue and fine-tune the work we started with NEH and our partners two years ago,” said Sarah Gard, Dole Institute senior archivist and head of collections. “The more accessible we can make these collections, the more people will be able to learn from them. Citizens being able to see and understand how our government functions is critical to our democracy.”

This new phase of the project is slated to run until June 2025. Over the next two years, the Dole Archives will contribute over 12,000 pages of previously digitized materials related to disability policy – primarily about the Americans with Disabilities Act – from former U.S. Sen. Bob Dole’s collections and the Alec Vachon Papers, who was a legislative assistant and disability adviser for Dole. The archives also will digitize and contribute approximately 10,000 pages of Dole’s weekly schedules from 1972-1995. They will also begin cataloging papers from former lawmaker Elizabeth Dole’s term in the U.S. Senate for North Carolina and hope to contribute selections pertinent to her congressional service.

“While some of these items are already digitized, this project enables the Dole Archives to enhance our metadata – information about materials – using schema developed with partner institutions. We also aim to create and include accurate, full-text versions of archival documents, which will aid patrons and researchers who may need to use screen readers to peruse the material due to visual impairments,” said Marla Weaver, assistant archivist for digital initiatives at the Dole Institute. “I see congressional archives as the stories that had to be told to pass and refine legislation which has shaped and continues to shape our lives – like the Americans with Disabilities Act. It’s especially gratifying to be able to make these stories more available and accessible to the communities they have served for generations now.”

The project addresses many practical access barriers to using congressional archives. Unlike presidential papers, which are centralized in one location, congressional collections are located throughout the United States. For researchers, collections may be difficult to use, both because of a lack of travel funding and varying levels of description in the archives.

“The personal papers of members of Congress are vitally important for understanding Congress as an institution, public policy development and the many diverse stories that comprise the American experience,” said Danielle Emerling, project director and congressional and political papers archivist at West Virginia University Libraries. “We are honored to have support from the NEH to make more congressional archives available to everyone.”

This project expands on a 2021 NEH foundations grant of nearly $60,000 that resulted in a prototype portal and included archives from WVU Libraries, the Dole Institute of Politics and the Robert C. Byrd Center for Congressional History and Education. The project has also received a $39,000 LYRASIS Catalyst Fund grant and a $10,000 grant from Association of Centers for the Study of Congress in 2022, which supported the development and fine-tuning of the portal’s functionality.

The NEH’s Humanities Collections and Reference Resources program supports projects that provide an essential underpinning for scholarship, education and public programming in the humanities. The project was selected for funding, in part, by a new agencywide special initiative, “American Tapestry: Weaving Together Past, Present, and Future,” which invests in humanities projects and new programs that support civics education, foster civic engagement, increase media and information literacy, and examine threats to America’s democracy.

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KU News Service

1450 Jayhawk Blvd.

Lawrence KS 66045

Phone: 785-864-3256

Fax: 785-864-3339

[email protected]

http://www.news.ku.edu

Erinn Barcomb-Peterson, director of news and media relations, [email protected]

Today’s News is a free service from the Office of Public Affairs