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제목 How an intriguing quantum phenomenon can spur advances in next-generation electronics
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작성일 2020.02.19 15:45:25 조회수 34
summary New study shows how a quantum-mechanical property in solids can result in more efficient electronic
prof. 물리학과 김정우 교수님

 

PRESS RELEASE                                                                                             

 

How an intriguing quantum phenomenon can spur advances in next-generation electronics

 

New study shows how a quantum-mechanical property in solids can result in more efficient electronic devices

 

Researchers at Incheon National University find a novel quantum mechanics-driven approach to manipulate the light-induced motion of charges in atomic layers of a material. This study has opened doors for various future optoelectronic applications and generation of advanced next-generation devices.

 

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The proposed approach offers a platform for independently controlling both charge and spin electron currents. Photo Courtesy: Shutterstock


Berry curvature (BC) is an elusive quantum-mechanical property of solids, which has recently been found to play a crucial role in unusual dynamics of the motion of charges of certain materials. More specifically, the dipole component of BC (a property of conducting electrons)—which arises from a lack of inversion symmetry (a phenomenon in which molecules are symmetrically arranged in a geometric space) has shown several potential applications in electronic devices.

 

But, the BC dipoles found in currently studied materials show these useful properties under low-frequency (and hence low-energy) light only, which limits their applications, and thus scientists have been trying to find ways to fully explore the potential of BC dipoles. In a new study in Nature Communications, a research team from Incheon National University in Korea, including Dr. Jeongwoo Kim, found a novel mechanism to generate a large BC dipole for high-frequency applications. Dr. Kim says, “Our motivation was that we wanted to expand the applications of BC and its intriguing quantum phenomena. In this study, we revealed a way to utilize BC by using ferroelectricity.”

 

To begin with, they studied a two-atom-thick layer of tin telluride (SnTe) that can produce ferroelectricity. This means that the material holds an electric polarization that can be reversed by applying an external electric field. In addition, SnTe monolayers exhibit photocurrents, meaning that exposing them to light triggers the movement of electrons. Interestingly, on studying the BC dipoles in these materials, the research team found a direct relationship between BC and ferroelectricity in this and similar materials. “The fundamental relation between ferroelectricity and the BC dipole that we revealed is the counterpart of the well-known relationship between ferromagnetism and the BC monopole,” explains Dr. Kim.

 

The ability to manipulate BC dipoles has multiple applications in conventional electronics, but it can also prove useful in next-generation devices. By strategically inverting the ferroelectric polarization of the material and circular polarization of the incident light (that is, the direction of rotation of the light wave as it advances through space), it is possible to independently manipulate two types of currents: electric currents and spin currents (an intrinsic property of electrons that dictates its charge). The ability to create and control currents of electrons with a certain spin is key in the rising field of spintronics, which could provide us with unbelievably fast and energy-efficient devices. “We present an intriguing method for controlling spin and charge photo-induced currents; the large BC dipole found in this type of ferroelectric systems provide a new approach for multifunctional optoelectronic and optospintronic applications,” remarks Dr. Kim. This study gives hope for researchers to find novel engineering applications using this type of fascinating phenomena.

 

 

Reference

Authors:

Jeongwoo Kim1,2, Kyoung-Whan Kim3,4, Dongbin Shin1, Sang-Hoon Lee5, Jairo Sinova4,6, Noejung Park1 and Hosub Jin1*

Title of original paper:

 

Prediction of ferroelectricity-driven Berry curvature enabling charge- and spin-controllable photocurrent in tin telluride monolayers

Journal:

Nature Communications

DOI:

https://doi.org/10.1038/s41467-019-11964-6

Affiliations:

1Department of Physics, Ulsan National Institute of Science and Technology

2Department of Physics, Incheon National University

3Center for Spintronics, Korea Institute of Science and Technology

4Institute of Physics, Johannes Gutenberg University Mainz

5Korea Institute for Advanced Study

6Institute of Physics, Academy of Sciences of the Czech Republic

 

*Corresponding author’s email: hsjin@unist.ac.kr

 

 

About Incheon National University

Incheon National University (INU) is a comprehensive, student-focused university. It was founded in 1979 and given university status in 1988. One of the largest universities in South Korea, it houses nearly 14,000 students and 500 faculty members. In 2010, INU merged with Incheon City College to expand capacity and open more curricula. With its commitment to academic excellence and an unrelenting devotion to innovative research, INU offers its students real-world internship experiences. INU not only focuses on studying and learning but also strives to provide a supportive environment for students to follow their passion, grow, and, as their slogan says, be INspired.

 

Website: /mbshome/mbs/inuengl/index.html

 

About the author

Dr. Kim received his undergraduate and Ph.D. degree from POSTECH. He worked as a postdoctoral researcher at UC Irvine and joined UNIST as a research professor. He is now working as an associate professor at Incheon National University. His research focuses on the theoretical study of topological materials and emergent quantum phenomena using state-of-the-art first principles calculations. Recently, Dr. Kim has been working on the Berry curvature physics and its related photovoltaic responses.

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