Article
Chemistry, Multidisciplinary
Zijie Dai, Manukumara Manjappa, Yunkun Yang, Thomas Cai Wei Tan, Bo Qiang, Song Han, Liang Jie Wong, Faxian Xiu, Weiwei Liu, Ranjan Singh
Summary: Cadmium arsenide, a Dirac semimetal, shows remarkable optical nonlinearity and high electron mobility at terahertz frequencies, offering potential for high-performance electronic and photonic devices. The active control of photoconductivity in ultrathin films allows for low-power, ultrafast modulation of terahertz waves.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Wenjie Zhang, Yunkun Yang, Peng Suo, Kaiwen Sun, Jun Peng, Xian Lin, Faxian Xiu, Guohong Ma
Summary: The photocarrier dynamics in Cd3As2 film was investigated using time-resolved terahertz spectroscopy. The results showed that photoexcitation led to a sudden increase in THz photoconductivity, followed by a single exponential relaxation. The relaxation time increased with temperature, while the lifetime remained almost constant above 220 K. The fitting of a model revealed a narrow energy gap around the Dirac node.
Article
Chemistry, Multidisciplinary
Changhua Bao, Qian Li, Sheng Xu, Shaohua Zhou, Xiang-Yu Zeng, Haoyuan Zhong, Qixuan Gao, Laipeng Luo, Dong Sun, Tian-Long Xia, Shuyun Zhou
Summary: This study reveals the ultrafast dynamics of Dirac fermions in a 3D Dirac semimetal, showing their cooling mechanism and population inversion phenomenon. The linear dependence of relaxation rate on energy suggests cooling through intraband relaxation, and the observation of accumulated photoexcited carriers in the conduction band indicates population inversion with a relatively long lifetime compared to 2D graphene.
Article
Physics, Applied
A. D. Rice, J. N. Nelson, C. Brooks, S. Lany, K. Alberi
Summary: Cd3As2 provides a stable platform for studying the physics of three-dimensional Dirac semimetals. By introducing extrinsic dopants, the electron concentration can be tuned without substantial changes in the band structure, allowing for intentional design of Fermi-level position for device applications.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Run Xiao, Junyi Zhang, Juan Chamorro, Jinwoong Kim, Tyrel M. McQueen, David Vanderbilt, Morteza Kayyalha, Yi Li, Nitin Samarth
Summary: We investigated the integer quantum Hall effect in Cd3As2 thin films with strong to moderate quantum confinement. We observed the effect not only in the spin-polarized lowest Landau level (filling factor v = 1), but also in the spin-degenerate higher index Landau levels with even filling factors (v = 2, 4, 6). As the quantum confinement increased, we also observed a lifting of the Landau-level spin degeneracy at v = 3, which manifested as an anomaly in the longitudinal and Hall resistivities.
Article
Chemistry, Multidisciplinary
Zhaohang Xue, Zipu Fan, Xin Liao, Yaolong Li, Yulu Qin, Guanyu Zhang, Xiaoming Song, Zhi-Min Liao, Dong Sun, Guowei Lu, Qihuang Gong
Summary: The artificial engineering of photoresponse is crucial for optoelectronic applications, and in this study, a metasurface on a semimetallic Cd3As2 nanoplate was designed and fabricated to improve its thermoelectric photoresponse. The metasurface enhanced light absorption and resulted in a temperature gradient, contributing to the thermoelectric photoresponse. The power-dependent and wavelength-dependent measurements confirmed the excellent photoresponse characteristics of the metasurface device, including a linearly dependent photoresponse and efficient separation of photoexcited carriers. The designed metasurface device also demonstrated an anisotropic polarization-dependent photoresponse. This study highlights the potential of metasurfaces in controlling the photoresponse of semimetallic materials.
Article
Optics
Yan Cheng, Wenhan Cao, Guangqing Wang, Xiaoyong He, Fangting Lin, Feng Liu
Summary: By depositing a trapezoidal dielectric stripe on a 3D Dirac semimetal hybrid plasmonic waveguide, the thermal tunable propagation properties in the terahertz regime were systematically investigated. The results show that the width of the trapezoidal stripe affects the propagation length and figure of merit (FOM), with both decreasing as the upper side width increases. The propagation properties are also strongly influenced by temperature, with a modulation depth of more than 96% within the range of 3-600 K.
Article
Chemistry, Multidisciplinary
Gregory M. Stephen, Aubrey T. Hanbicki, Timo Schumann, Jeremy T. Robinson, Manik Goyal, Susanne Stemmer, Adam L. Friedman
Summary: The research demonstrates robust spin transport in Cd3As2 films with long spin-coherence lengths and high spin diffusion lengths, which are essential steps towards realizing spintronic devices.
Article
Materials Science, Multidisciplinary
G. Krizman, J. Bermejo-Ortiz, M. Goyal, A. C. Lygo, J. Wang, Z. Zhang, B. A. Assaf, S. Stemmer, L. A. de Vaulchier, Y. Guldner
Summary: In this work, the strain tuning of the Dirac nodes in Cd3As2 is demonstrated, showing that strain can enhance the node separation and thereby change the topological properties of the semimetal.
Article
Chemistry, Multidisciplinary
Wenjie Zhang, Kaiwen Sun, Peng Suo, Xiaona Yan, Xian Lin, Zuanming Jin, Guohong Ma
Summary: By using optical pump Terahertz (THz) probe spectroscopy, the ultrafast photocarrier dynamics of SnS2 nanoflake film, a two-dimensional (2D) semiconductor, were studied at room temperature. The photoexcitation dynamics are closely related to the density of edge sites and defects in the nanoflakes, which can be controlled by adjusting the height of vertically aligned SnS2 during growth. The transient THz photoconductivity response of the films after photoexcitation at 400 nm can be well described by a bi-exponential decay function. The faster and slower processes are shorter in thinner films and independent of the pump fluence, suggesting that edge-site trapping and defect-assisted electron-hole recombination are responsible for the fast and slow decay processes, respectively. The experimental results highlight the importance of edge sites and defects in SnS2 nanoflakes for photocarrier relaxation and the understanding of their photoelectrochemical performance.
Article
Multidisciplinary Sciences
Wei Lu, Zipu Fan, Yunkun Yang, Junchao Ma, Jiawei Lai, Xiaoming Song, Xiao Zhuo, Zhaoran Xu, Jing Liu, Xiaodong Hu, Shuyun Zhou, Faxian Xiu, Jinluo Cheng, Dong Sun
Summary: This study reveals the transient photothermoelectric response of Dirac semimetallic Cd3As2, namely the photo-Seebeck effect and photo-Nernst effect, by studying the terahertz emission from the transient photocurrent induced by these effects. The response clearly indicates an order of magnitude enhancement on transient photothermoelectric current generation when a weak magnetic field is applied. These results highlight the enhancement of thermoelectric performance can be achieved in topological Dirac semimetals based on the Nernst effect.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Natsuki Kanda, Yuta Murotani, Takuya Matsuda, Manik Goyal, Salva Salmani-Rezaie, Jun Yoshinobu, Susanne Stemmer, Ryusuke Matsunaga
Summary: We investigate the ultrafast dynamics in photoexcited Dirac semimetal Cd3As2 thin films and observe the merging of nonthermal electrons and existing carriers under high-density excitation. We also demonstrate the dominant effect of an 80% reduction in refractive index on the nonequilibrium infrared response, which can be utilized for designing ultrafast switches in active optoelectronics.
Article
Chemistry, Multidisciplinary
Huang Xu, Fucong Fei, Zhiqingzi Chen, Xiangyan Bo, Zhe Sun, Xiangang Wan, Li Han, Lin Wang, Kaixuan Zhang, Jiazhen Zhang, Gang Chen, Changlong Liu, Wanlong Guo, Luhan Yang, Dacheng Wei, Fengqi Song, Xiaoshuang Chen, Wei Lu
Summary: This study achieved a type-II Dirac semimetal Ir1-xPtxTe2 with a protected crystal structure and tunable Fermi level through Pt doping, showing excellent performance at terahertz frequencies. Van der Waals integration with Dirac semimetals exhibited superb detector performance comparable to state-of-the-art detectors.
Article
Nanoscience & Nanotechnology
W. Yu, D. X. Rademacher, N. R. Valdez, M. A. Rodriguez, T. M. Nenoff, W. Pan
Summary: This study analyzes the weak antilocalization behavior in Dirac semimetal Cd3As2 thin flake under low magnetic field. The results show that the phase coherence length increases with decreasing temperature at high temperatures and tends to saturate below 3 K. Additionally, three independent electron transport channels are found.
Article
Materials Science, Multidisciplinary
Jie Guo, Xinguo Zhao, Naikun Sun, Xiaofei Xiao, Wei Liu, Zhidong Zhang
Summary: The research focuses on tunable magneto-transport properties by adjusting Mn-doping in Cd3As2 compound, which affects Fermi level positions and transforms diamagnetic Cd3As2 to antiferromagnetic compound. Introduction of Mn atoms allows control of topological protected Dirac materials by manipulating antiferromagnetic order parameters. The study may pave a way for further investigating antiferromagnetic topological Dirac semimetal and expand the potential applications in optoelectronics and spintronics.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Enze Zhang, Xian Xu, Ce Huang, Yi-Chao Zou, Linfeng Ai, Shanshan Liu, Pengliang Leng, Zehao Jia, Yuda Zhang, Minhao Zhao, Zihan Li, Yunkun Yang, Jinyu Liu, Sarah J. Haigh, Zhiqiang Mao, Faxian Xiu
Summary: The study discovered a dissipationless re-entrant state and a significant drop in magnetoresistance in Ta2PdS5 nanostrips. Time-dependent Ginzburg-Landau calculations revealed that the phenomenon is due to the increased energy barrier suppressing vortex motion at the edges. Both experiments and simulations demonstrate that this giant re-entrance of superconductivity occurs only in certain geometrical regimes.
Article
Materials Science, Multidisciplinary
Xingchao Zhang, Rui Pan, Yunkun Yang, Xianchao Liu, Jiayue Han, Hongxi Zhou, Jun Gou, Faxian Xiu, Jun Wang
Summary: The discovery of three-dimensional topological Dirac/Weyl semi-metal has opened up new possibilities for advanced photodetectors. Cadmium arsenide (Cd3As2) is a highly representative semi-metal with ultra-high charge mobility and strong light-matter interaction. Photodetector prototypes based on Cd3As2 display high responsivity and performance, especially when combined with Cd3As2/CuPc heterojunction design.
Article
Chemistry, Multidisciplinary
Zhengzheng Liu, Manchen Hu, Juan Du, Tongchao Shi, Ziyu Wang, Zeyu Zhang, Zhiping Hu, Zijun Zhan, Keqiang Chen, Weimin Liu, Jiang Tang, Han Zhang, Yuxin Leng, Ruxin Li
Summary: Research on quasi-2D perovskites has shown promising laser performance at subwavelength scale, indicating potential applications in next-generation integrated laser sources.
Article
Chemistry, Physical
Wei Zhang, Wenqi Xu, Guoxian Zhang, Jie Kong, Xinmiao Niu, Julian M. W. Chan, Weimin Liu, Andong Xia
Summary: In this study, the intramolecular charge delocalization/localization of a newly synthesized acceptor-donor-acceptor molecule was intensively investigated using femtosecond stimulated Raman scattering and femtosecond transient absorption spectroscopy. The nature of the relaxed S-1 state was found to be strongly influenced by solvent polarity, with symmetric delocalized intramolecular charge transfer characters occurring in apolar solvent and asymmetric localized ICT characters appearing in polar solvent due to solvation. The solvation dynamics extracted from fs-TA were consistent with the time constants obtained by FSRS, but FSRS clearly tracked the excited state intramolecular charge transfer delocalization/localization.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Qiu-Shi Ma, Wenjie Zhang, Chunwei Wang, Ruihua Pu, Cheng-Wei Ju, Xian Lin, Zeyu Zhang, Weimin Liu, Ruxin Li
Summary: This study demonstrates the importance of the effective electric field introduced by the substrate in controlling the charge transfer pathway in TMDs/Gr heterojunctions, and proposes a physical picture to explain the process.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Jiaming Chen, Peng Suo, Wenjie Zhang, Hong Ma, Jibo Fu, Di Li, Xian Lin, Xiaona Yan, Weimin Liu, Zuanming Jin, Guo-Hong Ma, Jianquan Yao
Summary: In this study, transient terahertz spectroscopy was employed to investigate the nonequilibrium carrier dynamics and its temperature dependence in MoTe2. The experimental result demonstrated for the first time the dynamic formation of small polarons in a MoTe2 Weyl semimetal, which is of fundamental importance for understanding the optically driven enhancement of electron-phonon coupling, temperature-induced quantum phase transition, and the design of a MoTe2-based far-infrared photodetector.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
Wei Lu, Zipu Fan, Yunkun Yang, Junchao Ma, Jiawei Lai, Xiaoming Song, Xiao Zhuo, Zhaoran Xu, Jing Liu, Xiaodong Hu, Shuyun Zhou, Faxian Xiu, Jinluo Cheng, Dong Sun
Summary: This study reveals the transient photothermoelectric response of Dirac semimetallic Cd3As2, namely the photo-Seebeck effect and photo-Nernst effect, by studying the terahertz emission from the transient photocurrent induced by these effects. The response clearly indicates an order of magnitude enhancement on transient photothermoelectric current generation when a weak magnetic field is applied. These results highlight the enhancement of thermoelectric performance can be achieved in topological Dirac semimetals based on the Nernst effect.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Minhao Zhao, Zhongbo Yan, Xiaoyi Xie, Yunkun Yang, Pengliang Leng, Mykhaylo Ozerov, Dayu Yan, Youguo Shi, Jinshan Yang, Faxian Xiu, Shaoming Dong
Summary: This study investigates the magneto-optical properties of Weyl semimetal NbP under Voigt geometry and discovers abundant Landau level transition modes. The results provide insight into the location and evolution of the Fermi energy with magnetic fields. The combination of magneto-optical spectra under Voigt and Faraday geometry proves effective in determining key properties of topological materials.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jinwei Li, Ruihua Pu, Xiaoyan He, Qimingxing Chen, Suhong Liu, Weimin Liu, Jianfeng Li
Summary: A method is proposed to address the lack of organic fluorophores with high quantum yields and low liver retention in the NIR-II window by encapsulating phosphorylated fluorescent dyes into biodegradable calcium phosphate nanoparticles. By co-precipitation, the quantum yields of the fluorescent dyes in aqueous solution are significantly increased through a phenomenon called "precipitation-enhanced emission". The co-precipitation also changes the micro-environment and improves the metabolism of the nanoparticles in the liver, enabling high-contrast vascular visualization and breast tumor detection.
Article
Chemistry, Multidisciplinary
Ziyu Wang, Ya Zhang, Cheng Chen, Ruixue Zhu, Jiaming Jiang, Tsu-Chien Weng, Quanjiang Ji, Yifan Huang, Chong Fang, Weimin Liu
Summary: This study utilized femtosecond stimulated Raman spectroscopy and various time-resolved electronic spectroscopies, aided by quantum calculations, to investigate the red fluorescent protein mKeima with a large Stokes shift. It revealed the photocycle and isomerization process of mKeima, and identified the trans-isomer as the dominant contributor to the large Stokes shift emission.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Zhiyuan Zhao, Ruihua Pu, Ziyu Wang, Jiaming Jiang, Weimin Liu
Summary: Light-induced reduction of graphene oxide (GO) is a promising method to produce reduced GO (rGO) without using harsh chemicals. However, the physicochemical mechanisms underlying photoreduction are still controversial, whether GO is reduced through direct excitation or through solvated electron production. Distinguishing GO photoreduction dynamics from solvated electron dynamics is challenging due to the similar electronic absorption responses.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Ruihua Pu, Ziyu Wang, Ruixue Zhu, Jiaming Jiang, Tsu-Chien Weng, Yifan Huang, Weimin Liu
Summary: Phototherapy is an effective and safe method for reducing high levels of ZZ-BR in the serum of newborns. This study used various spectroscopic techniques and quantum chemical calculations to investigate the primary configurational isomerization dynamics of ZZ-BR in organic solvents. The results showed that upon photoexcitation, ultrafast configurational isomerization occurred, followed by intramolecular hydrogen-bond distortion and large-scale rotation of the two dipyrrinone halves of the ZZ-BR isomer in a few picoseconds. Most of the population returned back to ZZ-BR, while a small amount converted into stable BR isomers via structural isomerization.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Di Li, Shaobing Xiong, Bo Peng, Weimin Liu, Bo Li, Qinye Bao
Summary: In this study, the charge carrier extraction and recombination kinetics at the heterointerface of perovskite solar cells were investigated using ultrafast transient technologies. The results showed that the electron extraction, trap-induced electron capturing, and recombination processes at the heterointerface have specific time ranges. Furthermore, the insertion of a poly(vinyl alcohol) thin layer effectively enhanced electron extraction, blocked undesired electron back injection, and suppressed nonradiative recombination, leading to improved device parameters.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Di Li, Shaobing Xiong, Bo Peng, Weimin Liu, Bo Li, Qinye Bao
Summary: The suboptimal carrier dynamics at the heterointerface between the perovskite and charge transport layer severely limit the further improvement of the perovskite solar cells. By using ultrafast transient technologies, this study provides a comprehensive understanding of the charge carrier extraction and recombination kinetics at buried electron-selective heterointerfaces. It is demonstrated that the insertion of a poly(vinyl alcohol) (PVA) thin layer can effectively enhance the electron extraction, block electron back injection, and suppress nonradiative recombination, resulting in improved device parameters.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xiao Meng, Qian Hu, Xi Wang, Tengfei Ma, Weimin Liu, Xingjun Zhu, Chunhong Ye
Summary: Polymer-based room temperature phosphorescence is a promising field for applications such as organic light-emitting diodes, sensors, data encryption, and anti-counterfeiting. By introducing a rigid polymer network during polymerization, long-lived room temperature phosphorescence materials based on polycyclic aromatic hydrocarbons (PAHs) were successfully achieved, displaying high stability even under aqueous conditions.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
