Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > From heat to spin to electricity: Understanding spin transport in thermoelectric devices: Scientists shed light on how the magnetic properties of 2D interlayers can enhance spin accumulation effects in thermoelectric heterostructures

Thermoelectric materials will allow the efficient conversion of waste industrial heat into electricity. But to create effective thermoelectric materials, their underlying physics must be well understood.

CREDIT
Macrovector on Freepik
Thermoelectric materials will allow the efficient conversion of waste industrial heat into electricity. But to create effective thermoelectric materials, their underlying physics must be well understood. CREDIT Macrovector on Freepik

Abstract:
Thermoelectric materials, which can generate an electric voltage in the presence of a temperature difference, are currently an area of intense research; thermoelectric energy harvesting technology is among our best shots at greatly reducing the use of fossil fuels and helping prevent a worldwide energy crisis. However, there are various types of thermoelectric mechanisms, some of which are less understood despite recent efforts. A recent study from scientists in Korea aims to fill one such gap in knowledge. Read on to understand how!

From heat to spin to electricity: Understanding spin transport in thermoelectric devices: Scientists shed light on how the magnetic properties of 2D interlayers can enhance spin accumulation effects in thermoelectric heterostructures

Seoul, South Korea | Posted on January 29th, 2021

One of these mechanisms mentioned earlier is the spin Seebeck effect (SSE), which was discovered in 2008 by a research team led by Professor Eiji Saitoh from Tokyo University, Japan. The SSE is a phenomenon in which a temperature difference between a nonmagnetic and a ferromagnetic material creates a flow of spins. For thermoelectric energy harvesting purposes, the inverse SSE is especially important. In certain heterostructures, such as yttrium iron garnet--platinum (YIG/Pt), the spin flow generated by a temperature difference is transformed into a current with an electric charge, offering a way to generate electricity from the inverse SSE.

Because this spin-to-charge conversion is relatively inefficient in most known materials, researchers have tried inserting an atomically thin layer of molybdenum disulfide (MoS2) between the YIG and Pt layers. Though this approach has resulted in enhanced conversion, the underlying mechanisms behind the role of the 2D MoS2 layer in spin transport remains elusive.

To tackle this knowledge gap, Professor Sang-Kwon Lee of the Department of Physics at Chung-Ang University, Korea, has recently led an in-depth study on the topic, which has been published in Nano Letters. Various colleagues from Chung-Ang University participated, as well as Professor Saitoh, in an effort to understand the effect of 2D MoS2 on the thermoelectric power of YIG/Pt.

To this end, the scientists prepared two YIG/MoS2/Pt samples with different morphologies in the MoS2 layer, as well as a reference sample without MoS2 altogether. They prepared a measurement platform in which a temperature gradient can be enforced, a magnetic field applied, and the voltage difference caused by the ensuing spin flow monitored. Interestingly, they found that the inverse SSE, and in turn the thermoelectric performance of the whole heterostructure, can be either enhanced or diminished depending on the size and type of MoS2 used. In particular, using a holey MoS2 multilayer between the YIG and Pt layers yielded a 60% increase in thermoelectric power compared with YIG/Pt alone.

Through careful theoretical and experimental analyses, the scientists determined that this marked increase was caused by the promotion of two independent quantum phenomena that, together, account for the total inverse SSE. These are called the inverse spin Hall effect, and the inverse Rashba-Edelstein effect, which both produce a spin accumulation that is then converted into a charge current. Moreover, they investigated how the holes and defects in the MoS2 layer altered the magnetic properties of the heterostructure, leading to a favorable enhancement of the thermoelectric effect. Excited about the results, Lee remarks: "Our study is the first to prove that the magnetic properties of the interfacial layer cause spin fluctuations at the interface and ultimately increase spin accumulation, leading to a higher voltage and thermopower from the inverse SSE."

The results of this work represent a crucial piece in the puzzle of thermoelectric materials technology and could soon have real-world implications, as Lee explains: "Our findings reveal important opportunities for large-area thermoelectric energy harvesters with intermediate layers in the YIG/Pt system. They also provide essential information to understand the physics of the combined Rashba-Edelstein effect and SSE in spin transport." He adds that their SSE measurement platform could be of great help to investigate other types of quantum transport phenomena, such as the valley-driven Hall and Nernst effects.

Let us hope that thermoelectric technology progresses rapidly so that we can make our dreams of a more ecofriendly society a reality!

####

About Chung-Ang University
Chung-Ang University is a private comprehensive research university located in Seoul, South Korea. It was started as a kindergarten in 1918 and attained university status in 1953. It is fully accredited by the Ministry of Education of Korea. Chung-Ang University conducts research activities under the slogan of "Justice and Truth." Its new vision for completing 100 years is "The Global Creative Leader." Chung-Ang University offers undergraduate, postgraduate, and doctoral programs, which encompass a law school, management program, and medical school; it has 16 undergraduate and graduate schools each. Chung-Ang University's culture and arts programs are considered the best in Korea.
Website: https://neweng.cau.ac.kr/index.do

About Professor Sang-Kwon Lee

Dr. Sang-Kwon Lee obtained a PhD in Electronic Engineering from the Royal Institute of Technology, Sweden, in 2002. He was then first appointed Assistant Professor in the Department of Semiconductor Science and Technology at Chonbuk National University, Korea, in 2002 and subsequently joined the Department of Physics at Chung-Ang University in 2013 as a Professor. He is currently in charge of teaching Modern Physics and Mathematical Physics at Chung-Ang University. His research interests mainly revolve around solid state physics, such as the development and modelling of nanoscale thermoelectric materials and devices. He works on nanobiotechnology--such as nanobiological semiconducting sensors and cancer cell characterization through devices such as nanowires--microfluidics, and microelectromechanical systems. Currently, he is also interested in working on valley-related effects, such as the valley-Nernst effect, valley-Hall effect and various new Seebeck effects for energy harvesting applications in his quantum transport research lab at Chung-Ang University. He has over 140 publications to his name.

For more information, please click here

Contacts:
Seong-Kee Shin

Copyright © Chung-Ang University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

RELATED JOURNAL ARTICLE:

Related News Press

News and information

HKUST researchers develop a novel integration scheme for efficient coupling between III-V and silicon November 18th, 2022

Researchers at Purdue unlock light-matter interactions on sub-nanometer scales, leading to ‘picophotonics’ November 18th, 2022

Rice turns asphaltene into graphene for composites: ‘Flashed’ byproduct of crude oil could bolster materials, polymer inks November 18th, 2022

How “2D” materials expand: New technique that accurately measures how atom-thin materials expand when heated could help engineers develop faster, more powerful electronic devices November 18th, 2022

Magnetism/Magnons

Spin photonics to move forward with new anapole probe November 4th, 2022

New era of two-dimensional ferroelectrics: Reviewing layered van-der-Waals ferroelectrics for future nanoelectronics October 28th, 2022

Scientists take control of magnetism at the microscopic level: Neutrons reveal remarkable atomic behavior in thermoelectric materials for more efficient conversion of heat into electricity August 26th, 2022

‘Nanomagnetic’ computing can provide low-energy AI, researchers show May 6th, 2022

Possible Futures

HKUST researchers develop a novel integration scheme for efficient coupling between III-V and silicon November 18th, 2022

NIST’s grid of quantum islands could reveal secrets for powerful technologies November 18th, 2022

A new experiment pushes the boundaries of our understanding of topological quantum matter: The behavior of bosonic particles observed in a magnetic insulator fabricated from ruthenium chloride can be explained by a relatively new and little-studied physics phenomenon called the B November 18th, 2022

Trial by wind: Testing the heat resistance of carbon fiber-reinforced ultra-high-temperature ceramic matrix composites: Researchers use an arc-wind tunnel to test the heat resistance of carbon fiber reinforced ultra-high-temperature ceramic matrix composites November 18th, 2022

Discoveries

An on-chip time-lens generates ultrafast pulses: New device opens the doors to applications in communication, quantum computing, astronomy November 18th, 2022

Researchers at Purdue unlock light-matter interactions on sub-nanometer scales, leading to ‘picophotonics’ November 18th, 2022

Rice turns asphaltene into graphene for composites: ‘Flashed’ byproduct of crude oil could bolster materials, polymer inks November 18th, 2022

How “2D” materials expand: New technique that accurately measures how atom-thin materials expand when heated could help engineers develop faster, more powerful electronic devices November 18th, 2022

Announcements

HKUST researchers develop a novel integration scheme for efficient coupling between III-V and silicon November 18th, 2022

NIST’s grid of quantum islands could reveal secrets for powerful technologies November 18th, 2022

A new experiment pushes the boundaries of our understanding of topological quantum matter: The behavior of bosonic particles observed in a magnetic insulator fabricated from ruthenium chloride can be explained by a relatively new and little-studied physics phenomenon called the B November 18th, 2022

How “2D” materials expand: New technique that accurately measures how atom-thin materials expand when heated could help engineers develop faster, more powerful electronic devices November 18th, 2022

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

An on-chip time-lens generates ultrafast pulses: New device opens the doors to applications in communication, quantum computing, astronomy November 18th, 2022

Researchers at Purdue unlock light-matter interactions on sub-nanometer scales, leading to ‘picophotonics’ November 18th, 2022

Rice turns asphaltene into graphene for composites: ‘Flashed’ byproduct of crude oil could bolster materials, polymer inks November 18th, 2022

How “2D” materials expand: New technique that accurately measures how atom-thin materials expand when heated could help engineers develop faster, more powerful electronic devices November 18th, 2022

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Semi-nonlinear etchless lithium niobate waveguide with bound states in the continuum November 4th, 2022

Advances in thermoelectric power generation possible with various ‘metal chalcogenide’ materials, recent review shows November 4th, 2022

Improving the efficiency of nanogenerators that harvest static electricity October 28th, 2022

Scientists design electrolyte for lithium metal anodes for use in lithium metal batteries: Potential applications in metal battery systems that provide large-scale, sustainable energy October 7th, 2022

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project