Article
Physics, Multidisciplinary
Jonas Waetzel, Jamal Berakdar, E. Ya Sherman
Summary: This study explores the control of spin and spatial distribution in quantum dots using Terahertz (THz) vector beams with spatially textured polarization. The spatiotemporal evolution of spin and charge-current densities is analyzed, and the behavior of entanglement is quantified. The results show that both aspects can be efficiently controlled on the picosecond time scale by adjusting the parameters of the driving fields. The study also investigates the relationship between the electron g-factor and the type of spin-orbit coupling necessary for efficient interlevel transitions. These findings are important for the development of quantum dots in quantum information technology and for generating spin and charge currents as needed.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Joonhyung Lim, Yun Chang Choi, Dongsun Choi, I-Ya Chang, Kim Hyeon-Deuk, Kwang Seob Jeong, Kyungwon Kwak, Minhaeng Cho
Summary: Investigating the separate dynamics of electrons and holes is crucial for understanding semiconducting nanomaterials. Recent studies on n-type self-doped colloidal quantum dots have revealed unprecedented ultrafast intraband Auger processes and electron relaxation between spin orbit coupling states in the conduction band, providing insights into electron dynamics in higher quantum states coupled to surface states of CQDs.
Article
Materials Science, Multidisciplinary
Ahmal Jawad Zafar, Aranyo Mitra, Vadym Apalkov
Summary: In this study, the electron dynamics of a graphene nanoring in the presence of an ultrashort optical pulse were theoretically investigated. It was found that circularly polarized pulses can induce valley polarization in the graphene nanoring, whereas no valley polarization is observed in a graphene monolayer. The magnitude of the valley polarization in the graphene nanoring depends on the system parameters.
Article
Chemistry, Multidisciplinary
Vasilios Karanikolas, Takuya Iwasaki, Joel Henzie, Naoki Ikeda, Yusuke Yamauchi, Yutaka Wakayama, Takashi Kuroda, Kenji Watanabe, Takashi Taniguchi
Summary: High-quality emission centers in two-dimensional materials, such as carbon-enriched hexagonal boron nitride (hBN:C) layers, are promising for future photonic and optoelectronic applications. By placing hBN:C layers on Ag triangle nanoparticles (NPs), the decay time of atom-like color-center (CC) defects is accelerated to 46 ps from their bulk value of 350 ps, due to efficient excitation of plasmon modes. Simulations suggest higher Purcell values, and analysis reveals the influence of NP thickness on the Purcell factor of CCs. The ultrafast operation of CCs in hBN:C layers enables their use in demanding applications like single-photon emitters and quantum devices.
Article
Chemistry, Physical
Subham Burai, Nandan Ghorai, Hirendra N. Ghosh, Somen Mondal
Summary: Photostable perovskite quantum dot (PQD)-based composite systems have great potential for optoelectronic and photocatalysis applications. Researchers synthesized hydrophobic carbon dots (NC-Dots) and formed a composite system with PQD to enhance material stability and create a new generation of advanced materials. The dynamics and charge separation mechanism in PQD and NC-Dot-based composite systems were investigated, and different co-doped NC-Dots were synthesized to explore carrier dynamics. The findings showed that the dopant of NC-Dots influences the carrier-transfer process in the composite system, highlighting the importance of doped NC-Dots in photocatalysis. This study provides insights for improving efficiency in optoelectronics, photocatalysis, and related applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
Michael V. Davidovich, Igor S. Nefedov, Olga E. Glukhova, Michael M. Slepchenkov, J. Miguel Rubi
Summary: We analyze the steady-state thermal regime of a one-dimensional triode resonant tunnelling structure. High currents generated by resonant tunnelling produce heat that may damage the structure, making it crucial to determine the optimal operating conditions. By calculating the current generated in the device and applying the principle of energy conservation in the electrodes, we obtain the temperature reached for different electrode materials and analyze the importance of heat conduction and thermal radiation. Our results demonstrate that conduction is the dominant factor and the electrode material plays a key role in determining the temperature variation.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Applied
Kwan To Lai, Daniel Finkelstein-Shapiro, Arnaud Devos, Pierre-Adrien Mante
Summary: Picosecond ultrasonics is a reliable and versatile method for nondestructive materials' characterization as it studies laser-induced high-frequency strain waves. However, the detection of strain waves through convolution with a sensitivity function may blur much of the information.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Nandan Ghorai, Soumyadip Bhunia, Subham Burai, Hirendra N. Ghosh, Pradipta Purkayastha, Somen Mondal
Summary: This study synthesized and separated C-Dots with different emission peaks and investigated their carrier dynamics to reveal the origin and control mechanism of their fluorescence properties. These findings are of great significance for the design and development of new architectures based on C-Dots.
Article
Chemistry, Multidisciplinary
Yongjiu Yuan, Lan Jiang, Xin Li, Pei Zuo, Xueqiang Zhang, Yiling Lian, Yunlong Ma, Misheng Liang, Yang Zhao, Liangti Qu
Summary: In this study, an in situ strategy using a temporally and spatially shaped femtosecond laser was reported to synthesize MXene quantum dots (MQDs) uniformly attached to laser reduced graphene oxide (LRGO) for ultratransparent electrodes with exceptional electrochemical capacitance. The mechanism and plasma dynamics of the synthesis process were analyzed. The MQD/LRGO supercapacitor exhibited high flexibility and durability, ultrahigh energy density, long cycle life, excellent capacitance, high transparency, and high performance.
ADVANCED MATERIALS
(2022)
Review
Optics
V. S. Shevelev, A. Ishchenko, A. S. Vanetsev, V Nagirnyi, S. Omelkov
Summary: In recent years, there has been a growing demand for scintillation detectors with high time resolution in high-energy physics and medical imaging applications, especially for TOF-PET. Extensive research is currently being carried out on various materials to achieve the best time resolution.
JOURNAL OF LUMINESCENCE
(2022)
Article
Physics, Applied
Alex Widhalm, Sebastian Krehs, Dustin Siebert, Nand Lal Sharma, Timo Langer, Bjoern Jonas, Dirk Reuter, Andreas Thiede, Jens Foerstner, Artur Zrenner
Summary: This research utilizes low capacitance single quantum dot photodiodes as sensor devices for optoelectronic sampling of ultrafast electric signals. By utilizing the Stark effect, time-dependent electric signals are converted into time-dependent shifts of transition energy, which are accurately measured using resonant ps laser spectroscopy with photocurrent detection. This technique allows for sampling transients below 20 ps with a voltage resolution in the mV-range.
APPLIED PHYSICS LETTERS
(2021)
Review
Chemistry, Inorganic & Nuclear
Huaxin Liu, Xue Zhong, Qing Pan, Yi Zhang, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji
Summary: Among the carbon nanomaterials family, fluorescent carbon dots have emerged as significant members with outstanding characteristics and extensive applications. Despite the development of many synthesis strategies, achieving controllable synthesis remains challenging.
COORDINATION CHEMISTRY REVIEWS
(2024)
Article
Materials Science, Multidisciplinary
Ji-Chao Cheng, Ling-Yun Pan, Hong-Yu Tu, Hong-Jian Qi, Wen-Yu Ji, Fang-Fei Li, Ying-Hui Wang, Shu-Ping Xu, Zhi-Wei Men, Tian Cui
Summary: The study demonstrates that pressure can effectively adjust the interparticle spacing in binary nanoparticle superlattices, accelerating the electron transfer process. Additionally, the trap state of CdSe / ZnS QDs is found to impact the electron transfer process of BNSLs.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Stefano Bosco, Monica Benito, Christoph Adelsberger, Daniel Loss
Summary: The study proposes a minimal design modification of planar devices to enhance interactions for low-power ultrafast quantum operations. By establishing an asymmetric potential that strongly compresses the quantum dot, the confinement-induced spin-orbit interaction can be turned on and off at will in state-of-the-art qubits.
Article
Physics, Multidisciplinary
A. Stupakiewicz, C. S. Davies, K. Szerenos, D. Afanasiev, K. S. Rabinovich, A. V. Boris, A. Caviglia, A. V. Kimel, A. Kirilyuk
Summary: Researchers have achieved switching of magnetization in magnetic garnet films by ultrafast resonant excitation of longitudinal optical phonon modes, revealing the magneto-elastic mechanism of the switching. In contrast, excitation of strongly absorbing transverse phonon modes results in a thermal demagnetization effect only.
