- Random telegraph noises in vanadium-doped tungsten diselenide can be tuned with voltage polarity -
Random Telegraph Noise (RTN), a type of unwanted electronic noise, has long been
a nuisance in electronic systems, causing fluctuations and errors in signal processing.
However, a team of researchers from the Center for Integrated Nanostructure
Physics within the Institute for Basic Science (IBS), South Korea has made an
intriguing breakthrough that can potentially harness these fluctuations in
semiconductors. Led by Professor LEE Young Hee, the team reported that magnetic
fluctuations and their gigantic RTN signals can be generated in a vdW-layered
semiconductor by introducing vanadium in tungsten diselenide (V-WSe2) as a minute
magnetic dopant.
High contact resistance in lateral devices usually limits the manifestation of inherent
quantum states and further degrades the device’s performance. To overcome these
limitations, the researchers introduced a vertical magnetic tunneling junction device
by sandwiching a few layers of V-WSe2, a magnetic material, between the top and
bottom graphene electrodes. This device was able to manifest inherent quantum
states such as magnetic fluctuations and achieve high-amplitude RTN signals, even
with a small vanadium doping concentration of just ~0.2%.
Dr. Lan-Anh T. NGUYEN, the first author of the study said, “The key to success is
to realize large magnetic fluctuations in resistance by constructing vertical magnetic
tunneling junction devices with low contact resistance.”
Through the resistance measurement experiments using these devices, the
researchers observed RTNs with a high amplitude of up to 80% between welldefined two-stable states. In the bistable state, the magnetic fluctuations in
resistance prevail with temperature through the competition between intralayer and
interlayer coupling among the magnetic domains. They were able to identify this
bistable magnetic state through discrete Gaussian peaks in the RTN histogram with
distinctive features in the noise power spectrum.
Most importantly the researchers discovered the ability to switch the bistable
magnetic state and the cut-off frequency of the RTN simply by changing the voltage
polarity. This exciting discovery paves the way for the application of 1/2 noise
spectroscopy in magnetic semiconductors and offers magnetic switching capability in
spintronics.
“This is a first step to observe the bistable magnetic state from large resistance
fluctuations in magnetic semiconductors and offers the magnetic switching capability
with 1/f2 noises by means of simple voltage polarity in spintronics”, explained
Professor Lee.
Figure 1. Time evolution of RTN signals with the corresponding RTN histograms of
1/f 2feature in the noise power spectra at negative (a) and positive voltage (b). The
high-resistance state in the 1/f2 histogram represents antiparallel spin states
between layers (a) and the low-resistance state for parallel spin states between
layers (b).
Notes for editors
- References
Lan-Anh T. Nguyen, Jinbao Jiang, Tuan Dung Nguyen, Philip Kim, Min-Kyu Joo, Dinh Loc
Duong, Young Hee Lee. “Electrically tunable magnetic fluctuations in multilayered
vanadium-doped tungsten diselenide”. Nature Electronics, Aug 10 2023. DOI:
10.1038/s41928-023-01002-1
- Media Contact
For further information or to request media assistance, please contact Young Hee Lee,
Director of the Center for Integrated Nanostructure Physics (CINAP), Institute for Basic
Science (IBS) (+82-31-299-6507; leeyoung@skku.edu), or William I. Suh at the IBS Public
Relations Team (willisuh@ibs.re.kr).
- About the Institute for Basic Science (IBS)
IBS was founded in 2011 by the government of the Republic of Korea with the sole purpose
of driving forward the development of basic science in South Korea. IBS has 6 research
institutes and 33 research centers as of July 2023. There are eleven physics, three
mathematics, five chemistry, nine life science, two earth science, and three interdisciplinary
research centers.