An official website of the United States government
Amphiphilic complexes with luminescent rare earth metal ions suitable for Lanmuir-Blodgett (LB) deposition have been synthesized. LB monolayers with closely packed Eu complexes deposited directly on silver demonstrate significant far-field emission in contrast to the theoretical predictions of full quenching. Angular radiation and polarization patterns of the electric and magnetic dipole emission of Eu3+point to a high excitation efficiency of surface plasmon polaritons. Different luminescent behavior of closely packed emitters in comparison to diluted systems is tentatively attributed to the collective state of emitters in LB layers formed via near-field coupling with surface plasmons.
more »
« less
Magnetic dipole emission in resonant metal-dielectric-metal structures
We explore a possibility to control magnetic dipole emission with plasmonic cavities, placing Eu3+emitters inside profile-modulated metal-dielectric-metal structures. Significant variations in the branching ratio of the magnetic and electric dipole transitions are observed as the function of the thickness of the intermediate layer. The experimental results are confirmed with numerical simulations which account for cavity and gap plasmon resonances and predict modifications in the spontaneous emission spectrum as the function of the gap size and a strong directionality of the emission for small thicknesses of the intermediate layer. The implications of having a competition between electric and magnetic dipole relaxation channels in Eu3+are discussed.
more »
« less
- Award ID(s):
- 2112595
- PAR ID:
- 10376183
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 30
- Issue:
- 22
- ISSN:
- 1094-4087; OPEXFF
- Format(s):
- Medium: X Size: Article No. 40682
- Size(s):
- Article No. 40682
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Series of lanthanide‐containing metallic coordination complexes are frequently presented as structurally analogous, due to the similar chemical and coordinative properties of the lanthanides. In the case of chiral (LnIII[15‐MCN(L‐pheHA)‐5])3+metallacrowns (MCs), which are well established supramolecular hosts, the formation of dimers templated by a dicarboxylate guest (muconate) in solution of neutral pH is herein shown to have a unique dependence on the identity of the MC's central lanthanide. Calorimetric data and nuclear magnetic resonance diffusion studies demonstrate that MCs containing larger or smaller lanthanides as the central metal only form monomeric host‐guest complexes whereas analogues with intermediate lanthanides (for example, Eu, Gd, Dy) participate in formation of dimeric host‐guest‐host compartments. The driving force for the dimerization event across the series is thought to be a competition between formation of highly stable MCs (larger lanthanides) and optimally linked bridging guests (smaller lanthanides).more » « less
-
Abstract We combine synchrotron-based near-field infrared spectroscopy and first principles lattice dynamics calculations to explore the vibrational response of CrPS4in bulk, few-, and single-layer form. Analysis of the mode pattern reveals aC2 polar + chiral space group, no symmetry crossover as a function of layer number, and a series of non-monotonic frequency shifts in which modes with significant intralayer character harden on approach to the ultra-thin limit whereas those containing interlayer motion or more complicated displacement patterns soften and show inflection points or steps. This is different from MnPS3where phonons shift as 1/size2and are sensitive to the three-fold rotation about the metal center that drives the symmetry crossover. We discuss these differences as well as implications for properties such as electric polarization in terms of presence or absence of the P–P dimer and other aspects of local structure, sheet density, and size of the van der Waals gap.more » « less
-
A novel antiferromagnetic semiconductor, Eu 3 Sn 2 P 4 , has been discovered. Single crystals of Eu 3 Sn 2 P 4 were prepared using the Sn self-flux method. The crystal structure determined by single crystal X-ray diffraction shows that Eu 3 Sn 2 P 4 crystallizes in the orthorhombic structure with the space group Cmca (Pearson Symbol, oP 216). Six Sn–Sn dimers connected by P atoms form a Sn 12 P 24 crown-shaped cluster with a Eu atom located in the center. Magnetization measurements indicate that the system orders antiferromagnetically below a T N ∼14 K at a low field and undergoes a metamagnetic transition at a high field when T < T N . The effective magnetic moment is 7.41(3) μ B per Eu, corresponding to Eu 2+ . The electric resistivity reveals a non-monotonic temperature dependence with non-metallic behavior below ∼60 K, consistent with the band structure calculations. By fitting the data using the thermally activated resistivity formula, we estimate the energy gap to be ∼0.14 eV. Below T N , the resistivity tends to saturate, suggesting the reduction of charge-spin scattering.more » « less
-
Abstract Calibration of nuclear‐magnetic‐resonance‐based searches for axion‐like dark matter can be performed by free induction decay (FID) measurements. This manu‐ script describes FID experiments on several solid materials, motivated by the Cosmic Axion Spin Precession Experiment (CASPEr) program. Experiments with207Pb nuclear spins in ferroelectrics, lead magnesium niobate‐lead titanate (PbMg1/3Nb2/3O3) (PbTiO3)1/3(PMN‐PT) and lead zirconium titante PbZr0.52Ti0.48O3(PZT) are directly relevant to the CASPEr‐electric search for the electric dipole moment interaction of axion‐like dark matter. Experiments with31P nuclear spins in gadolinium‐doped hydroxypyromorphite Pb4.95Gd0.05(PO4)3OH (HPM:Gd) are used for apparatus calibration. The measurements characterized the nuclear spin ensemble coherence time and the magnetic resonance detection sensitivity for these samples. Calibration is performed using small tip‐angle pulses.more » « less
