Article
Materials Science, Multidisciplinary
Ekrem Taha Guldeste, Ceyhun Bulutay
Summary: This work introduces the synchrosqueezed wavelet transform to study the dipolar fluctuations of nuclear spins in a diamond crystal structure. The dynamics of the spin ensemble is analyzed based on zero-, single-, and double-quantum transitions. The study reveals the modulation of Overhauser field fluctuations and the presence of different beating patterns in the nuclear spin noise, providing spatial information about the spin clusters surrounding the central spin. Additionally, denoising techniques in the wavelet domain are demonstrated to effectively remove noise in the scalograms.
Article
Chemistry, Multidisciplinary
Gang Qiang, Evgeny A. . Zhukov, Eiko Evers, Dmitri R. . Yakovlev, Aleksandr A. . Golovatenko, Anna V. Rodina, Aleksei A. . Onushchenko, Manfred Bayer
Summary: The coherent spin dynamics of electrons in CdSe nanocrystals embedded in a glass matrix are studied using time-resolved Faraday ellipticity. The results show that only one Larmor precession frequency is detected, which is associated with the spin precession of resident electrons localized near the surface of nanocrystals. An additional nonoscillating component related to the hole spin polarization is observed at low temperature.
Article
Nanoscience & Nanotechnology
M. Milivojevic
Summary: The study explores the possibility of determining the Rashba spin-orbit coupling strength in InSb nanowire quantum dots by measuring the magnetic susceptibility of the two-electron system in a double quantum dot. It is found that the magnetic susceptibility reaches a maximal value when the spin-orbit and magnetic field are parallel/antiparallel, which can be used to extract the value of the Rashba parameter.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Chemistry, Multidisciplinary
Nianfang Wang, Seokhyeon Cheong, Da-Eun Yoon, Pan Lu, Hyunjoo Lee, Young Kuk Lee, Young-Shin Park, Doh C. Lee
Summary: Advances in nanotechnology have enabled precise design of catalytic sites for CO2 photoreduction, but most nanostructured photocatalysts have low activity. To address this issue, researchers constructed CdS nanosheets terminated by S2- atomic layers as intrinsic photocatalysts. Experimental results show that these nanostructures exhibit excellent photocatalytic performance, efficiently converting CO2 into CO with high selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Optics
Johannes K. Krondorfer, Andreas W. Hauser
Summary: This article investigates the possibility of coherent spin control in atoms or molecules via nuclear quadrupole resonance from first principles. It proposes a method called optical nuclear electric resonance (ONER) that uses pulsed optical excitations in the UV-visible light spectrum to modulate the electric field gradient. The realizations and limitations of ONER for atomically resolved spin manipulation are discussed and tested on 9Be as a benchmark system.
Review
Chemistry, Analytical
Masanori Ando, Hideya Kawasaki, Satoru Tamura, Yoshikazu Haramoto, Yasushi Shigeri
Summary: In recent years, there has been a growing demand for better and safer gas sensors that are smaller, lighter, energy-efficient, and cost-effective. This has led to the exploration of new gas sensor materials and optical gas sensor technology. This article reviews the recent advancements in conductometric and optical gas sensing technologies using CdS, CdSe, and CdTe.
Review
Chemistry, Multidisciplinary
Mathias Micheel, Raktim Baruah, Krishan Kumar, Maria Waechtler
Summary: This review discusses recent advances in the self-assembly of colloidal semiconductor nanocrystals into functional thin films with precise control over order and orientation. It provides a comprehensive overview of characterization methods used in the study of such ordered materials, and focuses on the two most promising methods of gas-liquid interfacial self-assembly and electric field driven deposition to generate superstructures with defined thickness, order, and orientation. The review also explores the relationship between superstructure and properties, specifically charge migration through the film and radiative processes, as well as addressing challenges and open questions in the field.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
T. S. Shamirzaev, D. R. Yakovlev, N. E. Kopteva, D. Kudlacik, M. M. Glazov, A. G. Krechetov, A. K. Gutakovskii, M. Bayer
Summary: Charged exciton recombination and spin dynamics in ultrathin InSb and AlSb quantum wells with an AlAs matrix were studied, revealing strong material intermixing and band alignment types. The circular polarization of photoluminescence Pc induced by a magnetic field showed nonmonotonic behavior at high magnetic fields. A kinetic equation model was developed to interpret the experiment and determine trion radiative lifetimes, spin relaxation times, and heavy-hole g factors for the studied structures.
Article
Multidisciplinary Sciences
Runyu Lu, Kaipeng Liu, Yue Ban
Summary: This paper focuses on the robust control of a singlet-triplet qubit in a nanowire double quantum dot using inverse engineering and shortcuts to adiabaticity (STA). The optimization of STA with respect to systematic errors and the application of optimal control techniques are explored.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Materials Science, Multidisciplinary
Qiang Cheng, Qing-Feng Sun
Summary: This study investigates the energy spectra of Dirac fermions confined in the quantum dot formed in the graphene/transition metal dichalcogenides (TMD) system under a perpendicular magnetic field. The obtained spin-valley polarized spectra can be classified into three types based on the energy gap values and are strongly influenced by the pseudospin potential and valley-dependent spin-orbit coupling unique to the electronic structure of the graphene/TMD system. The energy spectra exhibit sudden jumps, degeneracy-splitting-recombination behaviors, and continuous changes due to the Berry phase jumps and continuous change of the Berry phase. The evolutions of the levels by adjusting the valley-dependent spin-orbit coupling and pseudospin potential are also studied. These findings suggest the possibility of controlling the specific spin-valley freedom of electrons in the graphene/TMD system using a quantum dot setup.
Article
Nanoscience & Nanotechnology
Juhyeon Kim, Zachary Croft, Duncan G. Steel, Pei-Cheng Ku
Summary: This paper analyzes two laterally positioned quantum dot single-photon emitters in different semiconductor heterostructures. A controlled phase gate between two quantum dot spins based on Coulomb interaction is demonstrated. Increasing the bitrion coupling and spacing between the quantum dots improves the gate fidelity. The study also shows an enhanced bitrion coupling in In(Ga)N quantum dots.
Article
Optics
Xiao-Feng Shi
Summary: This paper presents a theory for cooling 87Sr nuclear-spin qubits in a weak magnetic field. The theory involves laser excitation of the 5s5p 3P1 state to a nearby state with mJ-dependent AC Stark shifts that are larger than the hyperfine interaction. This effectively suppresses nuclear-spin mixing caused by the hyperfine interaction. Sideband cooling via the AC Stark-shifted 3P1 state quenched by the clock state leads to nuclear-spin-preserving spontaneous emission back to the ground state. The theory is not only compatible with low magnetic fields but also applicable to nuclear-spin qubits defined by the two lowest Zeeman substates.
Article
Materials Science, Multidisciplinary
Zhongyuan Guan, Haihang Ye, Peiwen Lv, Lijin Wang, Jing Zhang, Bin Zou, Aiwei Tang
Summary: The growth of multinary Cu-based chalcogenide nanocrystals involves the presence of copper vacancies affecting exciton recombination, the high reaction activity of selenium leading to red-shift in photoluminescence maximum, and the competitive relationship between growth and diffusion of zinc resulting in red- or blue-shift in photoluminescence maximum.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
J. Dimuna, T. Boyett, I. Miotkowski, A. K. Ramdas, T. M. Pekarek, J. T. Haraldsen
Summary: By using computational and experimental techniques, the effects of titanium doping on the +2 oxidation of CdSe crystal are examined. The presence of a robust spin-1 magnetic state of Ti is confirmed through stoichiometry and magnetization measurements. Density functional theory is used to investigate the electronic and magnetic states, and it is found that the Ti-d impurity band transitions from a metallic state to a semiconducting state as the Hubbard U parameter changes, resulting in the formation of the +2 state for the Ti ion.
Article
Materials Science, Multidisciplinary
T. S. Shamirzaev, J. Rautert, D. R. Yakovlev, M. Bayer
Summary: The study focuses on exciton recombination and spin dynamics in monolayer-thick (In,Al)As/AlAs quantum wells, revealing significant dependence of exciton recombination time and photoluminescence intensity on magnetic field strength and orientation. Magnetic field-induced effects, such as slowing down recombination and reducing intensity, are observed, along with nonmonotonic behavior of circular polarization of photoluminescence. The results also provide insights into the g factor, radiative and nonradiative recombination times, and spin relaxation times of electrons and heavy holes bound in the exciton.
