With apologies to Isaac Asimov, the most exciting phrase to hear in science isn’t “Eureka,” but “That’s funny…”
A “that’s funny” moment in a Colorado State University physics lab has led to a fundamental discovery that could play a key role in next-generation microelectronics.
Publishing in Nature Physics April 25, the scientists led by Mingzhong Wu, professor of physics in CSU’s College of Natural Sciences, are the first to demonstrate using non-polarized light to produce what’s called a spin voltage – a unit of power produced from the quantum spinning of an individual electron. Controlling electron spins for use in memory and logic applications is a relatively new field called spin electronics, or spintronics, and the subject of the 2007 Nobel Prize in Physics.
Spintronics exploits the notion that electron spins can be manipulated and used to process and store information, with a fraction of the power needed in conventional electronics. Wu and his group’s passion is to find new, better ways to control electron spins, the physics of which isn’t yet completely understood.
Consider that the iPhone and every electronic device out there is built upon centuries of science around charge current – positive or negative charges flowing through a device. The perennial problem is the enormous power consumption of charge-current devices, and the electrical resistance that causes power loss in the form of heat – which is why your laptop keeps overheating.
These power and heat barriers limit smaller, more powerful electronics. And that’s why science is turning to spintronics, because it offers a completely new way of making a device work. No charge current is necessary to utilize power from an electron spin. All that’s needed is a magnetic field or a magnetic material, which can orient the spins “up” or “down.” The up and down spins are the analog to positive and negative charges.
Existing methods for creating spin currents include using a charge current (which kind of defeats the purpose), microwaves, or a heat source. But for the first time, the CSU team has used light – or in the quantum world, photons – to generate their spin currents.
Other scientists have done similar things, but with a special kind of polarized light. Here, the CSU scientists used plain unpolarized light – “a halogen bulb purchased at Ace Hardware,” said graduate student David Ellsworth, who is the first author on the paper. They demonstrated a “pure” spin current – involving no charge movement. It was an unprecedented feat.
Curiosity leads to discovery
The breakthrough came about while the scientists were studying spin currents created by the heat from their Ace Hardware bulb. They noticed some background data they couldn’t explain: the “that’s funny” moment.
Ever curious, they checked all possibilities and determined that this seemingly light-induced spin current could be a new quantum phenomenon. They tested it by designing unique control measurements involving different magnetic insulators and metallic thin films, such as platinum. After replicating their results in the lab, they turned to theoreticians at the University of California Irvine and Fudan University to help them interpret the physics of what they’d discovered. These experts became co-authors on the Nature Physics paper.
Wu said the discovery is too new to think about real-world applications; scientists are continuing to make breakthroughs in the theoretical understanding of spin currents. “Just like with the photovoltaic effect when it was first discovered, no one thought at first of a solar cell,” Wu said. “Technologies take time before they are used in real devices. This is a fundamental, new discovery.”
Said Jake Roberts, chair of the CSU Department of Physics: “There have been tremendous technical advances in controlling light. What I see in this discovery is that now, they’ve linked light to spin control. Using a simple light source to produce a spin current offers new opportunities for power control and generation.”
Continuing the inquiry
The researchers will continue exploring making spin currents by swapping out materials and trying different light sources. They demonstrated light control in the infrared range, and moving into the visible or UV range would likely offer more robust applications for devices, Ellsworth said.
“The framework for generating and detecting spin currents is non-trivial,” he explained. “Meanwhile, there are hundreds of years of generating charge currents and knowing how to measure them and manipulate them and characterize them. Spintronics is a new field, and devices are just now coming onto the market that utilize some small part of this.”
The Latest on: Spin currents
via Google News
The Latest on: Spin currents
- InterActiveCorp: Taking Match Group And ANGI Homeservices Out For A Spinon August 16, 2019 at 9:13 am
A recent InterActiveCorp (IAC) announcement suggests the potential spin-offs of Match Group (MTCH) and ANGI Homeservices (ANGI) are close to materializing. At the current share prices of MTCH and ...
- Logic Switch Uses No Electric Current:on August 15, 2019 at 5:33 pm
"The method uses a voltage-controlled topological spin switch (VTOPSS) that requires only electric fields, rather than currents, to switch between two Boolean logic states, greatly reducing the heat ...
- Spin-Off Expert Bets On Madison Square Garden (MSG)on August 15, 2019 at 7:06 am
The current share price is $290. Why does MSG trade at such a discount? Conglomerate Discount. Dolan Discount After the spin-off, the conglomerate discount will evaporate, but the Dolan discount will ...
- Are Scientific Journals Reliable? Study Exposes How Authors ‘Spin’ Abstractson August 14, 2019 at 6:57 pm
Spin in this specific context means using of specific reporting ... authors are free to pick and choose the details that they include in the abstract section. The researchers of the current study are ...
- The Spin: Lightfoot, Pritzker willing to deal with Vegas consultant’s concerns over Chicago casinoon August 13, 2019 at 2:06 am
Win or lose —The state’s hired consultant writes this: “The current regulatory construct ... Pelosi’s gathering with Illinois Democrats, Mellet tells The Spin. Bipartisan shows: Republicans and ...
- Scout24 to explore sale or spin-off of autos platformon August 12, 2019 at 10:58 pm
These could include a sale or spin-off," Hartmann told Reuters at Scout24's headquarters ... Scout24 management is looking into whether it can increase the company's current leverage ratio of around ...
- Spin Master Bolsters Hedbanz Presence Globally with Acquisition of International IP and Launch of All New Hedbanz Appon August 12, 2019 at 5:00 am
To date, Spin Master has produced nine television series, including the relaunched Bakugan: Battle Planet and current hit PAW Patrol, which is broadcast in over 160 countries and territories globally.
- The Spin: Jeffrey Epstein court records mention Tom Pritzker, cousin to Gov. J.B. Pritzker, Penny Pritzkeron August 12, 2019 at 2:38 am
The new hospital will sit just west of the current one but have the same mailing address ... Click here to read the story. Thanks for reading The Spin, the Tribune’s politics newsletter. Sign up here ...
- Mallinckrodt (MNK) Q2 Earnings Beat, Generics Spin-off on Holdon August 7, 2019 at 11:16 am
Update on Specialty Generics Separation In December 2018, the company announced that it intends to spin-off the Specialty Generics business into a new company. However, based on current market ...
- Understanding spin-start clock motorson August 7, 2019 at 8:51 am
That secondary winding is short circuited as if we shorted the "E secondary" in Figure 1 so that current will flow in that bobbin akin ...  An interesting flaw in these spin-start clocks was that ...
via Bing News