Article
Materials Science, Multidisciplinary
Aanchal Sati, Anil Kumar, Vikash Mishra, Kamal Warshi, Preeti Pokhriyal, Archna Sagdeo, P. R. Sagdeo
Summary: The temperature-dependent impedance spectroscopy, optical absorption spectroscopy, and Raman spectroscopic measurements were conducted on BaTiO3 to investigate the correlation between dielectric loss, band gap, and electron-phonon coupling. It was found that in the tetragonal phase, dielectric loss increases slightly with temperature, while in the cubic phase, it decreases. Moreover, the electron-phonon coupling parameter increases with temperature and exhibits a sharp increase at the tetragonal to cubic transition temperature.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Anupriya Singh, Soumitra Satapathi
Summary: The study investigates the temperature-dependent band gap engineering and reversible thermochromism in all-inorganic antimony-based Cs3Sb2Br9 single crystals. The crystals change color from yellow to deep orange at high temperatures and return to yellow at room temperature. High-energy phonons are identified as the primary cause for the reduction in indirect band gap.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Nicholas Dale, M. Iqbal Bakti Utama, Dongkyu Lee, Nicolas Leconte, Sihan Zhao, Kyunghoon Lee, Takashi Taniguchi, Kenji Watanabe, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Roland J. Koch, Jeil Jung, Feng Wang, Alessandra Lanzara
Summary: Using ARPES, the effects of many-body interactions and displacement field on the band structure of twisted bilayer graphene (tBG) devices at an intermediate (3 degrees) twist angle are studied. The observed renormalization of bands at the K points suggests the influence of moire models of the Hartree-Fock interaction. Evidence of correlation-enhanced inversion symmetry-breaking, shown as tunable gaps at the Dirac points, suggests a new approach to engineering band structure and symmetry-breaking phases in moire heterostructures.
Article
Chemistry, Physical
Minghuan Cui, Chaochao Qin, Zhongpo Zhou, Yuanzhi Jiang, Shichen Zhang, Zeye Yuan, Mingjian Yuan, Kun Yu, Yuhai Jiang, Yufang Liu
Summary: Organic-inorganic layered perovskites are materials with complex lattice dynamics, and the coupling between photons and phonons plays a significant role in device applications. This study investigates the dynamics of photon-phonon coupling and finds that solvent engineering has a significant impact on lattice vibrations and coherent phonons.
Article
Chemistry, Physical
Minghuan Cui, Chaochao Qin, Zhongpo Zhou, Yuanzhi Jiang, Shichen Zhang, Zeye Yuan, Mingjian Yuan, Kun Yu, Yuhai Jiang, Yufang Liu
Summary: Organic-inorganic layered perovskites, consisting of alternating layers of organic cations and lead halide octahedra, exhibit complex lattice dynamics due to the interaction between soft organic molecules and stiff ionic crystals. This study investigates the electron-optical phonon coupling dynamics in these materials using ultrafast pump-probe transient absorption spectroscopy. The results show that solvent engineering significantly affects the lattice vibrational modes and coherent phonon dynamics, providing new insights for the development of optoelectronic devices based on layered perovskites.
Article
Chemistry, Physical
Cameron C. L. Underwood, J. David Carey, S. Ravi P. Silva
Summary: The research shows a nonlinear band gap behavior with Sn content in mixed phase 2D Ruddlesden-Popper perovskites, providing critical insight for the design of future metal alloy 2D perovskite materials. The tunable energy band discontinuity positions may point to intraband transitions of interest to device engineers.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Jan-Hendrik Poehls, Marissa MacIver, Sevan Chanakian, Alexandra Zevalkink, Yu-Chih Tseng, Yurij Mozharivskyj
Summary: Thermoelectric materials, which convert thermal energy into electrical energy, have the potential to address the global climate crisis. This study explores the use of lithium to reduce the lattice thermal conductivity of chalcopyrite CuGaTe2, improving its thermoelectric performance. The findings show that introducing lithium leads to a significant reduction in lattice thermal conductivity without compromising the electronic properties, resulting in an increase in the average zT of Cu0.90Li0.05Ag0.05GaTe2 by 56%.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jose D. Mella, Hernan L. Calvo, Luis E. F. Foa Torres
Summary: This report discusses the effects of electron-phonon interaction in materials, particularly in graphene. It shows that this interaction can lead to the formation of a gap bridged by unique edge states, with a distinctive locking among propagation direction, valley, and phonon mode. These findings shed light on how to utilize these unconventional states in quantum research.
Article
Materials Science, Multidisciplinary
Suvodeep Paul, Saheb Karak, Annie Mathew, Ankita Ram, Surajit Saha
Summary: This study provides a comprehensive analysis of the phonon properties of transition metal dichalcogenides (TMDs) MoS2 and MoTe2, examining the effects of temperature, laser excitations, polarization, and flake thickness on phonon characteristics. The anharmonicity variations are explained in terms of phonon symmetries, electron-phonon coupling, and phonon-phonon interactions. Furthermore, the impact of the underlying substrate on the anharmonic properties of in-plane and out-of-plane phonons is estimated, elucidating the intrinsic phonon properties of two-dimensional layered materials.
Article
Chemistry, Multidisciplinary
Davide Campi, Simran Kumari, Nicola Marzari
Summary: Two-dimensional superconductors are of great interest for both their fundamental physics and potential applications in quantum computing. The material W2N3 is predicted to have a remarkably high superconducting critical temperature of 21 K, making it a unique platform to study different coupling regimes and test the limits of current theories of superconductivity. This material also shows the possibility of coexistence of superconductivity and topologically nontrivial edge states.
Article
Chemistry, Multidisciplinary
Alexander D. Christodoulides, Peijun Guo, Lingyun Dai, Justin M. Hoffman, Xiaotong Li, Xiaobing Zuo, Daniel Rosenmann, Alexandra Brumberg, Mercouri G. Kanatzidis, Richard D. Schaller, Jonathan A. Malen
Summary: The newly developed RP phase perovskites based on MAPbI(3) show enhanced environmental stability compared to MAPbI(3) but degrade at elevated temperatures. Experimental results reveal that the thermal conductivities decrease with increasing n, primarily due to the influence of coherent phonons and reduced group velocity in RP phases.
Article
Chemistry, Physical
Inigo Gonzalez de Arrieta, Leire del Campo, Domingos De Sousa Meneses
Summary: The dielectric function of a cerium oxide nanopowder was investigated using infrared spectroscopy, with Bergman's spectral representation and a semi-quantum dielectric function model enabling an accurate retrieval of the main features of lattice dynamics. The observed differences between the nanopowder and single crystal dielectric functions can be explained by phonon confinement, due to the absence of significant lattice strain or vacancy concentration. The results were validated by comparison to literature data and additional spectroscopic techniques, as well as by direct measurements of powder filling factors.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Physics, Condensed Matter
Jayanta Bhattacharjee, S. D. Singh
Summary: In this study, electron-phonon interactions in β-Ga2O3 were investigated by studying the temperature dependent photoluminescence of the red emission line. The observed emission was determined to be excitonic recombination at low temperatures. Different phonon modes were found to interact with different emission lines. In the low temperature region, carrier transfer between emission lines was observed.
SOLID STATE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Natalya S. Fedorova, Andrea Cepellotti, Boris Kozinsky
Summary: This study uncovers a new phenomenon where the electrical conductivity decreases with carrier concentration, the Seebeck coefficient reverses sign even at high doping, and the power factor exhibits an unusual second peak in materials with multiple bands crossing near the Fermi level. The origin and magnitude of this effect are explained, and general design rules for enhancing performance in thermoelectric materials are identified.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
X. Yang, A. Jena, F. Meng, S. Wen, J. Ma, X. Li, W. Li
Summary: In this study, the effect of electron-phonon interaction on the lattice thermal conductivity of graphene was investigated using first-principles calculations. It was found that the indirect coupling between flexural acoustic phonons and electrons has a significant impact on thermal conductivity in graphene, particularly due to the dominance of normal processes. Additionally, an unusual minimum thermal conductivity was observed at a specific charge carrier density in graphene.
MATERIALS TODAY PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Haizhen Wang, Lihan Liang, Junze Li, Wendian Yao, Dehui Li
Summary: In this study, single-crystalline DJP microplates with uniform rectangular morphology were successfully synthesized using a space-confined aqueous method. These microplates, functioning as whispering-gallery-mode cavities, exhibit significantly enhanced Rashba IX emission through efficient photon recycling in the Rashba indirect gap. The efficient photon recycling can substantially extend the exciton transport length, which is conducive to light-harvesting devices.
ADVANCED OPTICAL MATERIALS
(2022)
Review
Materials Science, Multidisciplinary
Haizhen Wang, Zhe Li, Zeyi Liu, Jikun Fu, Tianyou Shan, Xiaoyi Yang, Qiyuan Lei, Yujie Yang, Dehui Li
Summary: This article introduces the working principles, device structure and materials of flexible capacitive pressure sensors, as well as strategies to improve their sensitivity and their applications in wearable electronic devices. In addition, the current challenges and future research directions of flexible capacitive pressure sensors are also discussed.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Optics
Tong Ye, Yongzhuo Li, Junze Li, Hongzhi Shen, Junwen Ren, Cun-Zheng Ning, Dehui Li
Summary: The study demonstrated an efficient and nonvolatile electrochemical-doping method for manipulating the valley polarization of interlayer excitons in van der Waals heterostructures. A significant excitonic/valley-polarized hysteresis was observed in WS2/WSe2 heterostructures, leading to the successful demonstration of a nonvolatile valley-addressable memory. These findings open up new possibilities for nonvolatile valley-addressable memory and may inspire further research on valleytronic devices.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Junwen Ren, Hongzhi Shen, Zeyi Liu, Ming Xu, Dehui Li
Summary: Artificial synapses based on two-dimensional transition metal dichalcogenides (TMDs) have attracted attention for their potential in neuromorphic computing. In this study, a lateral WSe2 homojunction was successfully used to create an artificial synapse that emulates biological synaptic functions and allows for a large synaptic weight change. The transition from short-term memory (STM) to long-term memory (LTM) can also be achieved with a simpler structure, aiding in the integration of transistor-based artificial synapses.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Wancai Li, Long Hu, Jiaqi Ma, Chuanxiu Jiang, Shuai Zhang, Yingying Chen, Junchao Hu, Xinfeng Liu, Tom Wu, Dehui Li
Summary: This study reports a new approach to significantly enhance the emission efficiency of self-trapped excitons via interfacial excitonic energy transfer in 2D/quantum dots perovskite heterostructures. The enhanced self-trapped exciton emission in the heterostructures can be attributed to Dexter energy transfer taking place at the interface. This interface-based strategy provides a simple and practical way to improve the emission efficiency of self-trapped excitons for photoelectric devices.
Article
Nanoscience & Nanotechnology
Yu-Tao Li, Jun-Ze Li, Li Ren, Kui Xu, Sheng Chen, Lei Han, Hang Liu, Xiao-Liang Guo, Du-Li Yu, De-Hui Li, Li Ding, Lian-Mao Peng, Tian-Ling Ren
Summary: In this study, a 2D halide perovskite/carbon nanotubes (CNTs) heterostructure optical synapse was constructed to qualitatively observe ion aggregation or dissipation in 2D perovskite using CNTs as nanoprobes. The results showed that light significantly changed the memory curve of the reconfigurable optical synapses. Molecular dynamic simulations demonstrated the dynamic process of ion migration in the heterostructure and revealed the electrostatic interaction effect of nonequilibrium charge distribution of CNTs on iodide ions. Through the synapses, an effective light-controlled process was achieved to regulate the performance of the weight-value discretized BP neural network.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Engineering, Manufacturing
Haizhen Wang, Yingying Chen, Dehui Li
Summary: Two-dimensional (2D)/quasi-2D organic-inorganic halide perovskites are naturally formed multiple quantum wells with layered structure, large exciton binding energy, strong nonlinear optical effect, tunable bandgap, improved environmental stability, and excellent optoelectronic properties. The choice of long organic chains endows them with tunable electron-phonon coupling strength, chirality, or ferroelectricity properties. In this paper, the recent achievements and potential applications of 2D/quasi-2D perovskite-based heterostructures in various optoelectronic devices are reviewed, along with current challenges and further research directions.
INTERNATIONAL JOURNAL OF EXTREME MANUFACTURING
(2023)
Article
Nanoscience & Nanotechnology
Tong Sun, Zhongyang Bai, Zhaoying Li, Yongshan Liu, Yaxuan Chen, Fan Xiong, Linliang Chen, Yong Xu, Fan Zhang, Dong Li, Junze Li, Weisheng Zhao, Tianxiao Nie, Lianggong Wen
Summary: Broadband spintronic terahertz radiation is efficiently generated by spin-to-charge current conversion in a ferromagnetic/nonmagnetic heterostructure. This study proposes a set of femtosecond laser-driven versatile spintronic terahertz devices by integrating meta-antenna structures with W/CoFeB/Pt nanolayer stacks. These monolithic integrated devices exhibit spintronic terahertz wave emission, spectral modulation, and polarization manipulation simultaneously.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Dong Yang, Junchao Hu, Yingying Chen, Dehui Li
Summary: Interlayer excitons (IXs) are observed in two-dimensional (2D) perovskite/transition-metal dichalcogenide (TMD) heterostructures, regardless of lattice and momentum mismatch, and thermal annealing. The abundant choices of 2D perovskites and TMDs, along with strong interlayer coupling, make these heterostructures attractive for studying IXs. This study explores the impact of organic cations in 2D perovskites on IXs emission in heterostructures containing monolayer WSe2. The results demonstrate that organic cations can change the exciton binding energy and emission peak of IXs, attributed to the difference in dielectric constants. The findings provide important insights into 2D perovskite/TMD heterointerfaces and offer potential for tunable exciton devices based on IXs.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Tinghao Lin, Wendian Yao, Zeyi Liu, Dehui Li, Xinliang Zhang
Summary: Researchers have demonstrated a linear polarization polarimeter based on vertically stacked ReS2 nanobelt devices with a designed twist angle. The device shows high responsivity (959 A W-1) without external gate voltage. The ReS2 nanobelt photodetector exhibits a strong polarization-sensitive photoresponse with a linear dichroic ratio of 1.72 at 665 nm. This study provides a simple approach for future polarization-sensitive optoelectronic devices.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Longcan Chen, Wendian Yao, Tong Su, Ruihan Xu, Shuhui Wan, Jielin Yang, Xiaoniu Peng, Dehui Li, Hui Yuan, Yingshuang Fu, Xina Wang
Summary: In this work, heterobilayered and heteromultilayered SnS2/MoS2 vdWhs were prepared to study the correlation between electron-phonon coupling (EPC) and valley depolarization. The results showed that the E-2g(1) mode of MoS2 in the vdWhs exhibited a red shift, and the vibration intensity transitioned from isotropic to anisotropic. The valley depolarization of the MoS2 in the vdWhs was found to be layer-dependent, and a strong EPC effect also resulted in layer-dependent Raman shifts.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yue Hu, Xinglin Wen, Jiamin Lin, Wendian Yao, Yingying Chen, Junze Li, Sijie Chen, Lei Wang, Weigao Xu, Dehui Li
Summary: In this study, selective enhancement of singlet and triplet interlayer exciton (IX) emission was achieved by coupling WS2/WSe2 heterostructure to a SiO2 microsphere cavity. This all-optical approach allows for emission intensity enhancement and control of the emissive IX species at room temperature. Moreover, an all-optical valley polarization switch with a high on/off ratio of 35 was demonstrated.
Article
Nanoscience & Nanotechnology
Xinglin Wen, Yunxi Zhou, Sijie Chen, Wendian Yao, Dehui Li
Summary: By utilizing a new mechanism of near-field interference, directional routing of valley exciton emission of monolayer WSe2 can be achieved with a symmetric nano-slits array. This provides a convenient and promising strategy towards on-chip integrated valleytronic devices at room temperature.
Article
Chemistry, Multidisciplinary
Anran Wang, Wendian Yao, Zidi Yang, Dingqi Zheng, Songlin Li, Yi Shi, Dehui Li, Fengqiu Wang
Summary: The broadband transient dynamics of interlayer excitation in a WS2/WSe2 heterostructure are investigated, revealing its nearly constant lifetimes across a wide energy range, in contrast to the energy-dependent dynamics of intralayer excitons in monolayer WSe2. This work enriches the understanding of interlayer couplings in van der Waals heterostructures.