Article
Nanoscience & Nanotechnology
Hyeonjun Baek, Mauro Brotons-Gisbert, Aidan Campbell, Valerio Vitale, Johannes Lischner, Kenji Watanabe, Takashi Taniguchi, Brian D. Gerardot
Summary: Trapped excitons in a molybdenum diselenide/tungsten diselenide heterobilayer device can serve as a sensitive optical probe for carrier filling. By mapping the spatial positions of individual trapped excitons, it is possible to spectrally track the emitters as the moire lattice is filled with excess carriers, providing insights into Coulomb interaction energies and visualizing charge correlated states.
NATURE NANOTECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Harley D. Scammell, Oleg P. Sushkov
Summary: This work provides a theoretical description for both strong and weak excitonic bound states, with particular application to biased bilayer graphene. A wave function approach is valid only in the weak-binding regime, while the Bethe-Salpeter equation is used for the strong-binding regime. Our analysis demonstrates that the strong-binding regime is also possible for biased bilayer graphene.
Article
Nanoscience & Nanotechnology
Xin-Rui Mao, Zeng-Kai Shao, Hong-Yi Luan, Shao-Lei Wang, Ren-Min Ma
Summary: A new type of optical device called magic-angle laser has been proposed and developed in this study, utilizing twisted photonic graphene superlattices for localized feedback of light fields. Unlike conventional laser cavities, magic-angle lasers do not require discontinuity of material property or disorder, and can achieve strong field confinement and high quality factor nanocavities through a simple twist.
NATURE NANOTECHNOLOGY
(2021)
Article
Multidisciplinary Sciences
Madeline Van Winkle, Isaac M. Craig, Stephen Carr, Medha Dandu, Karen C. Bustillo, Jim Ciston, Colin Ophus, Takashi Taniguchi, Kenji Watanabe, Archana Raja, Sinead M. Griffin, D. Kwabena Bediako
Summary: The authors quantitatively characterized the mechanical deformations of small-angle twisted bilayers and heterobilayers of 2D semiconductors using interferometric 4D scanning transmission electron microscopy. They found that lattice reconstruction and strain accumulation are crucial for defining the electronic structure of two-dimensional moire superlattices. Local rotations dominate relaxation in twisted homobilayers, while local dilations are prominent in heterobilayers with large lattice mismatch. Encapsulation of the moire layers in hBN further enhances and localizes the in-plane reconstruction pathways.
NATURE COMMUNICATIONS
(2023)
Article
Optics
Fanzhou Lv, Zhihang Wang, Yudie Huang, Jiaxu Chen, Junqiao La, Dongda Wu, Zhicheng Guo, Yujun Liu, Yufeng Zhang, Yi Wang, Wenxin Wang
Summary: In this paper, the coherent optical properties of a plasmonic system consisting of metal nanoparticle arrays and a WS2 thin film were investigated. The coupling factor, energy splitting, and temporal dynamics of this coherent coupling phenomenon were quantitatively revealed, and it was found that the exciton behavior of WS2 is modulated by surface lattice resonances. This work may open up new possibilities for the coherent modulation of polariton and plasmon devices.
Article
Materials Science, Multidisciplinary
O. Ruiz-Cigarrillo, L. F. Lastras-Martinez, E. A. Cerda-Mendez, G. Flores-Rangel, C. A. Bravo-Velazquez, R. E. Balderas-Navarro, A. Lastras-Martinez, N. A. Ulloa-Castillo, K. Biermann, P. Santos
Summary: This study investigated in-plane optical anisotropies in symmetric and asymmetric double quantum wells using reflectance anisotropy spectroscopy. It was found that a reduction in symmetry from D-2d to C-2v leads to an increase in reflectance anisotropy strength due to heavy- and light-hole mixing. Residual anisotropies in symmetric DQWs originate from QW interface asymmetry, while in asymmetric DQWs, the asymmetrical distribution of AlGaAs layers contributes to the increased RAS intensity.
Article
Multidisciplinary Sciences
Pasqual Rivera, Minhao He, Bumho Kim, Song Liu, Carmen Rubio-Verdu, Hyowon Moon, Lukas Mennel, Daniel A. Rhodes, Hongyi Yu, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, David G. Mandrus, Hanan Dery, Abhay Pasupathy, Dirk Englund, James Hone, Wang Yao, Xiaodong Xu
Summary: In this study, a new series of low energy excitonic emission lines in ultraclean monolayer WSe2 are reported, composed of three major peaks matching known phonons, and only appearing with electron doping. These excitonic satellites possess homogenous spatial and spectral distribution, strong power saturation, and anomalously long lifetimes.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Lior Verbitsky, Dipti Jasrasaria, Uri Banin, Eran Rabani
Summary: This study explores the structural, electronic, and optical properties of CdSe/CdS core-shell colloidal quantum dot molecules using atomistic approaches. The strain profile maps of free-standing colloidal dimers show negligible additional strain resulting from attachment. The electronic properties are described using a semiempirical pseudopotential model and the Bethe-Salpeter equation. The study analyzes the effects of strain, hybridization, quantum confinement, and electron-hole binding energies on the optical properties, and also investigates the influence of the dimensions of the neck and the shell thickness.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Xi Wang, Jiayi Zhu, Kyle L. Seyler, Pasqual Rivera, Huiyuan Zheng, Yingqi Wang, Minhao He, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, David G. Mandrus, Daniel R. Gamelin, Wang Yao, Xiaodong Xu
Summary: Researchers observed moire trions and their doping-dependent photoluminescence polarization in H-stacked MoSe2/WSe2 heterobilayers. As moire traps are filled with either electrons or holes, new sets of interlayer exciton photoluminescence peaks emerge with specific narrow linewidths. Circularly polarized photoluminescence reveals a switching polarization pattern as moire excitons transition from negatively charged to positively charged, driven by energy relaxation pathways during interlayer trion formation.
NATURE NANOTECHNOLOGY
(2021)
Article
Chemistry, Physical
Finn L. Sebastian, Nicolas F. Zorn, Simon Settele, Sebastian Lindenthal, Felix J. Berger, Christoph Bendel, Han Li, Benjamin S. Flavel, Jana Zaumseil
Summary: Researchers have proposed a direct quantification protocol based on a linear correlation that can accurately assess the defect density on the lattice of single-wall carbon nanotubes (SWCNTs) and determine the oscillator strengths of different defect types.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Yuan Chen, Haidong Liang, Leyi Loh, Yiwei Ho, Ivan Verzhbitskiy, Kenji Watanabe, Takashi Taniguchi, Michel Bosman, Andrew A. Bettiol, Goki Eda
Summary: We observe bound exciton (BX) complex manifolds in monolayer MoSe2 with intentionally created monoselenium vacancies (VSe) using proton beam irradiation. The emission intensity of different BX peaks exhibits contrasting dependence on electrostatic doping near the onset of free electron injection. These complexes, which are more strongly bound than trions and biexcitons, survive up to around 180 K and show moderate valley polarization memory, indicating partial free exciton character.
Article
Chemistry, Multidisciplinary
Shi-Jie Hou, Yi-Fan Yang, Zhong-hua Cui, Lorenz S. Cederbaum
Summary: Anions play an important role in chemistry, but their excited states are generally unstable. This study focused on two promising prototype candidates, Li@C-12 and Li@C-20 anions, and found stable doubly-excited states in addition to stable singly-excited states. The discovery provides insights into designing anions with stable valence singly- and doubly-excited states, and potential applications are mentioned.
Article
Multidisciplinary Sciences
Xuezhi Ma, Kaushik Kudtarkar, Yixin Chen, Preston Cunha, Yuan Ma, Kenji Watanabe, Takashi Taniguchi, Xiaofeng Qian, M. Cynthia Hipwell, Zi Jing Wong, Shoufeng Lan
Summary: This study introduces an efficient solution to manipulate dark excitons by reintroducing photonics bound states in the continuum (BICs), enabling giant enhancement and highly directional emission of dark excitons. The directional emission is coherent at room temperature, shown through polarization analyses and interference measurements.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Ming-Yu Kuo, Natalia Spitha, Matthew P. Hautzinger, Pei-Lun Hsieh, Jing Li, Dongxu Pan, Yuzhou Zhao, Lih-Juann Chen, Michael H. Huang, Song Jin, Yung-Jung Hsu, John C. Wright
Summary: This study successfully prepared 2D/3D halide perovskite heterostructures through solution growth, revealing differences in carrier transfer and recombination among different types of 2D/3D heterostructures. The findings provide insights into charge transfer mechanisms in these perovskite heterostructures and offer guidelines for designing better optoelectronic devices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
Erfu Liu, Elyse Barre, Jeremiah van Baren, Matthew Wilson, Takashi Taniguchi, Kenji Watanabe, Yong-Tao Cui, Nathaniel M. Gabor, Tony F. Heinz, Yia-Chung Chang, Chun Hung Lui
Summary: Moire superlattices formed by van der Waals materials can support a wide range of electronic phases including Mott insulators, superconductors, and generalized Wigner crystals. The coupling of moire trions to charge carriers in tungsten diselenide/molybdenum diselenide heterobilayers leads to the emergence of new excitonic crystals with distinct properties and behaviors, motivating further theoretical and experimental studies of higher-order electron correlation effects in moire superlattices.
Article
Materials Science, Multidisciplinary
M. V. Milovanovic, E. Dobardzic, Z. Papic
Article
Materials Science, Multidisciplinary
E. Dobardzic, M. Dimitrijevic, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
M. V. Milovanovic, S. Predin
Article
Materials Science, Multidisciplinary
N. Moran, A. Sterdyniak, I. Vidanovic, N. Regnault, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
J. Vucicevic, M. O. Goerbig, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
E. Dobardzic, M. V. Milovanovic, N. Regnault
Article
Materials Science, Multidisciplinary
E. Dobardzic, M. Dimitrijevic, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
S. Predin, A. Knezevic, M. Milovanovic
Summary: We propose a variant of dipole representation for composite fermions in a half-filled Landau level, incorporating the symmetry under particle-hole exchange. This is achieved by imposing a special constraint on the composite fermion and composite hole degrees of freedom in an enlarged space, ensuring that the resulting composite particle (dipole) is a symmetric object. We investigate an effective Hamiltonian that satisfies the constraint on the physical space and exhibits boost invariance at the Fermi level. The calculated Fermi liquid parameter F2 agrees well with the numerical investigations in Phys. Rev. Lett. 121, 147601 (2018).
Article
Materials Science, Multidisciplinary
M. Milovanovic, S. Djurdjevic
Summary: Theoretical predictions suggest the existence of particle-hole Pfaffian topological phases in a uniform system due to strong Landau level mixing. Studies on the quantum Hall bilayer have revealed an intermediate phase with mixed negative-flux p-wave pairing, indicating the presence of both intra- and inter-layer pairing correlations.
Article
Materials Science, Multidisciplinary
Dragoljub Gocanin, Sonja Predin, Marija Dimitrijevic Ciric, Voja Radovanovic, Milica Milovanovic
Summary: Building upon previous work, this study investigated a system of bosons at filling factor nu = 1 and derived the Dirac composite fermion theory for a half-filled Landau level. In the long-wavelength limit, a noncommutative field-theoretical description was proposed, which reproduced Son's theory with additional terms. The research found that particle-hole symmetry breaking led to weak and strong p-wave pairings in different Landau levels.
Article
Materials Science, Multidisciplinary
Stevan Durdevic, Milica Milovanovic
Article
Materials Science, Multidisciplinary
L. Antonic, J. Vucicevic, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
V. Raca, M. V. Milovanovic
Article
Materials Science, Multidisciplinary
M. V. Milovanovic
Article
Materials Science, Multidisciplinary
M. V. Milovanovic, M. Dimitrijevic Ciric, V. Juricic
