Title: Electric Field-Induced Metal-to-Insulator Phase Transition in Few-Layered MoSe2
The Metal-Insulator phase transition (MIT) is one of the most interesting phenomena to study particularly in two-dimensional transition-metal dichalcogendes (TMDCs). A few recent studies1,2 have indicated a possible MIT on MoS2 and ReS2, but the nature of the MIT is still enigmatic due to the interplay between charge carriers and disorder in 2D systems. We will present a potential MIT in few-layered MoSe2 FETs based on four-terminal conductivity measurements. Conductivities measured in multiple samples strongly demonstrate the insulating-to-metallic-like phase transition when the charge carrier density increased above a critical threshold. The nature of the phase transition will be discussed with an existing theoretical model.
1B. H. Moon et al, Nat Commun. 2018; 9: 2052. 2N. R. Pradhan et al, Nano Lett. 2015, 15, 12, 8377
*This work was performed, in part, at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. This work is also supported by NSF-DMR #1826886 and # 1900692. A portion of this work was performed at the NHMFL, which is supported by the NSF Cooperative Agreement No. DMR-1644779 and the State of Florida more »« less
Bucksbaum, P.(
, Bulletin of the American Physical Society)
Liwendowski, H.
(Ed.)
The electrons and atoms inside molecules can rearrange rapidly during photoexcitation or collisions, moving angstroms in a few femtoseconds or less. This non-classical many-body quantum evolution is far too small and too fast to be resolved in any imaging microscope, but if we could film it, what should we expect to see? New tools based on ultrafast lasers, electron accelerators, and x-ray free-electron lasers have now begun to record this motion with increasing detail, and for a growing array of atomic and molecular systems. Here I will attempt to answer the question, "So what?" What have we learned, and how are molecular movies guiding us toward future discoveries in AMO physics?
*Much of this work is supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Chemical Sciences, Geosciences, and Biosciences Division (CSGB). Other work described here has been supported by the National Science Foundation
Lee, Sunghwan; Lee, Donghun; Qin, Fei; Zhang, Yuxuan; Rothschild, Molly; Song, Han Wook; No, Kwangsoo(
, ECS Meeting Abstracts)
The discovery of oxide electronics is of increasing importance today as one of the most promising new technologies and manufacturing processes for a variety of electronic and optoelectronic applications such as next-generation displays, batteries, solar cells, memory devices, and photodetectors[1]. The high potential use seen in oxide electronics is due primarily to their high carrier mobilities and their ability to be fabricated at low temperatures[2]. However, since the majority of oxide semiconductors are n-type oxides, current applications are limited to unipolar devices, eventually developing oxide-based bipolar devices such as p-n diodes and complementary metal-oxide semiconductors. We have contributed to a wide range of oxide semiconductors and their electronics and optoelectronic device applications. Particularly, we have demonstrated n-type oxide-based thin film transistors (TFT), integrating In 2 O 3 -based n-type oxide semiconductors from binary cation materials to ternary cation species including InZnO, InGaZnO (IGZO), and InAlZnO. We have suggested channel/metallization contact strategies to achieve stable and high TFT performance[3, 4], identified vacancy-based native defect doping mechanisms[5], suggested interfacial buffer layers to promote charge injection capability[6], and established the role of third cation species on the carrier generation and carrier transport[7]. More recently, we have reported facile manufacturing of p-type SnOx through reactive magnetron sputtering from a Sn metal target[8]. The fabricated p-SnOx was found to be devoid of metallic phase of Sn from x-ray photoelectron spectroscopy and demonstrated stable performance in a fully oxide-based p-n heterojunction together with n-InGaZnO. The oxide-based p-n junctions exhibited a high rectification ratio greater than 10 3 at ±3 V, a low saturation current of ~2x10 -10 , and a small turn-on voltage of -0.5 V. In this presentation, we review recent achievements and still remaining issues in transition metal oxide semiconductors and their device applications, in particular, bipolar applications including p-n heterostructures and complementary metal-oxide-semiconductor devices as well as single polarity devices such as TFTs and memristors. In addition, the fundamental mechanisms of carrier transport behaviors and doping mechanisms that govern the performance of these oxide-based devices will also be discussed. ACKNOWLEDGMENT This work was supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 20011028) by KRISS. K.N. was supported by Basic Science Research Program (NRF-2021R11A1A01051246) through the NRF Korea funded by the Ministry of Education. REFERENCES [1] K. Nomura et al. , Nature, vol. 432, no. 7016, pp. 488-492, Nov 25 2004. [2] D. C. Paine et al. , Thin Solid Films, vol. 516, no. 17, pp. 5894-5898, Jul 1 2008. [3] S. Lee et al. , Journal of Applied Physics, vol. 109, no. 6, p. 063702, Mar 15 2011, Art. no. 063702. [4] S. Lee et al. , Applied Physics Letters, vol. 104, no. 25, p. 252103, 2014. [5] S. Lee et al. , Applied Physics Letters, vol. 102, no. 5, p. 052101, Feb 4 2013, Art. no. 052101. [6] M. Liu et al. , ACS Applied Electronic Materials, vol. 3, no. 6, pp. 2703-2711, 2021/06/22 2021. [7] A. Reed et al. , Journal of Materials Chemistry C, 10.1039/D0TC02655G vol. 8, no. 39, pp. 13798-13810, 2020. [8] D. H. Lee et al. , ACS Applied Materials & Interfaces, vol. 13, no. 46, pp. 55676-55686, 2021/11/24 2021.
Bate, Teagan; Varney, Megan; Taylor, Ezra; Dickie, Joshua; Chueh, Chih-Che; Norton, Michael M; Wu, Kun-Ta(
, Bulletin of the American Physical Society)
Active fluids have potential applications in micromixing, but little is known about the mixing kinematics of such systems with spatiotemporally-varying activity. To investigate, UV-activated caged ATP was used to activate controlled regions of microtubule-kinesin active fluid inducing a propagating active-passive interface. The mixing process of the system from non-uniform to uniform activity as the interface advanced was observed with fluorescent tracers and molecular dyes. At low Péclet numbers (diffusive transport), the active-inactive interface progressed toward the inactive area in a diffusion-like manner and at high Péclet numbers (convective transport), the active-inactive interface progressed in a superdiffusion-like manner. The results show mixing in non-uniform active fluid systems evolve from a complex interplay between the spatial distribution of ATP and its active transport. This active transport may be diffusion-like or superdiffusion-like depending on Péclet number and couples the spatiotemporal distribution of ATP and the subsequent localized active stresses of active fluid. Our work will inform the design of future microfluidic mixing applications and provide insight into intracellular mixing processes.
*T.E.B., E.H.T., J.H.D., and K.-T.W. acknowledge support from the National Science Foundation (NSF-CBET-2045621). C.-C. C. was supported through the National Science and Technology Council (NSTC), Taiwan (111-2221-E-006-102-MY3). M.M.N. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0022280).
Materials research provides the foundation
for the development of many new
technologies. Basic materials research in
the United States is supported by several
federal agencies, including the National
Science Foundation (NSF), Department
of Energy (DOE), and Department of
Defense (DoD). Federal agencies play a
critical role not only in funding research
at universities and national laboratories,
but also in forging collaborations with
industrial partners. At NSF, the Division
of Materials Research (DMR), in particular,
is dedicated to advancing fundamental
materials research through single
investigator grants, as well as through
research centers, such as the Materials
Research Science and Engineering
Centers. To help identify and highlight
important emerging areas of materials research,
funding agencies often solicit input
from the community by holding workshops
and conducting outreach at meetings
run by the Materials Research Society
(MRS) and other professional societies.
Dickie, Joshua H; Bate, Teagan; Varney, Megan; Taylor, Ezra; Chueh, Chih-Che; Norton, Michael M; Wu, Kun-Ta(
, Bulletin of the American Physical Society)
Active fluids with spatiotemporally varying activity have potential applications to micromixing; however previously existing active fluids models are not prepared to account for spatiotemporally-varying active stresses. Our experimental work used UV-activated caged ATP to activate controlled regions of microtubule-kinesin active fluid inducing a propagating active-passive interface. Here, we recapitulate our experimental results with two models. The first model redistributes an initial ATP distribution by Fick's law and translates the ATP distribution into a velocity profile by Michaelis-Menton kinetics. This model reproduces our experimental measurements for the low-Péclet number limit within 10% error without fitting parameters. However, as the model is diffusion based, it fails to capture the convective based superdiffusive-like behaviour at high Péclet numbers. Our second model introduces a spatiotemporally varying ATP field to an existing nematohydrodynamic active fluid model and then couples the active stresses to local ATP concentrations. This model is successful in qualitatively capturing the superdiffusive-like progression of the active-inactive interface for high Peclet number (convective transport) experimental cases. Our results show that new model frameworks are necessary for capturing the behaviour of active fluid with spatiotemporally varying activity.
*T.E.B., E.H.T., J.H.D., and K.-T.W. acknowledge support from the National Science Foundation (NSF-CBET-2045621). C.-C. C. was supported through the National Science and Technology Council (NSTC), Taiwan (111-2221-E-006-102-MY3). M.M.N. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0022280).
Pradhan, Nihar, Garcia, Carlos, Chakrabarti, Bhaswar, Nash, Jawnaye, Miller, Christina S., Raghavan, Dharmaraj, Karim, Alamgir, Stan, Liliana, Divan, Ralu, Rosenmann, Daniel, Sumant, Anirudha, and McGill, Stephen A. Electric Field-Induced Metal-to-Insulator Phase Transition in Few-Layered MoSe2. Retrieved from https://par.nsf.gov/biblio/10143374. Bulletin of the American Physical Society 65.1
Pradhan, Nihar, Garcia, Carlos, Chakrabarti, Bhaswar, Nash, Jawnaye, Miller, Christina S., Raghavan, Dharmaraj, Karim, Alamgir, Stan, Liliana, Divan, Ralu, Rosenmann, Daniel, Sumant, Anirudha, and McGill, Stephen A.
"Electric Field-Induced Metal-to-Insulator Phase Transition in Few-Layered MoSe2". Bulletin of the American Physical Society 65 (1). Country unknown/Code not available. https://par.nsf.gov/biblio/10143374.
@article{osti_10143374,
place = {Country unknown/Code not available},
title = {Electric Field-Induced Metal-to-Insulator Phase Transition in Few-Layered MoSe2},
url = {https://par.nsf.gov/biblio/10143374},
abstractNote = {The Metal-Insulator phase transition (MIT) is one of the most interesting phenomena to study particularly in two-dimensional transition-metal dichalcogendes (TMDCs). A few recent studies1,2 have indicated a possible MIT on MoS2 and ReS2, but the nature of the MIT is still enigmatic due to the interplay between charge carriers and disorder in 2D systems. We will present a potential MIT in few-layered MoSe2 FETs based on four-terminal conductivity measurements. Conductivities measured in multiple samples strongly demonstrate the insulating-to-metallic-like phase transition when the charge carrier density increased above a critical threshold. The nature of the phase transition will be discussed with an existing theoretical model. 1B. H. Moon et al, Nat Commun. 2018; 9: 2052. 2N. R. Pradhan et al, Nano Lett. 2015, 15, 12, 8377 *This work was performed, in part, at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. This work is also supported by NSF-DMR #1826886 and # 1900692. A portion of this work was performed at the NHMFL, which is supported by the NSF Cooperative Agreement No. DMR-1644779 and the State of Florida},
journal = {Bulletin of the American Physical Society},
volume = {65},
number = {1},
author = {Pradhan, Nihar and Garcia, Carlos and Chakrabarti, Bhaswar and Nash, Jawnaye and Miller, Christina S. and Raghavan, Dharmaraj and Karim, Alamgir and Stan, Liliana and Divan, Ralu and Rosenmann, Daniel and Sumant, Anirudha and McGill, Stephen A.},
}
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