DFT calculation of <sup>229</sup>thorium-doped magnesium fluoride for nuclear laser spectroscopy

Pimon, Martin; Gugler, Johannes; Mohn, P.; Kazakov, G.; Mauser, Norbert J.; Schumm, Thorsten

doi:10.1088/1361-648x/ab7c90

Cited by 17 publications

(21 citation statements)

References 54 publications

(83 reference statements)

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“…As the expected isomer excitation energy shifted into the VUV over the years (see Fig. 2.11), finding materials with suitable transparency became more challenging, converging on the family of fluoride single crystals [84,[99][100][101].…”

Section: Solid-state-clock Operation and Performancementioning

confidence: 99%

Nuclear clocks for testing fundamental physics

Peik

Schumm

Safronova

et al. 2021

Quantum Sci. Technol.

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109

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The low-energy, long-lived isomer in 229Th, first studied in the 1970s as an exotic feature in nuclear physics, continues to inspire a multidisciplinary community of physicists. It has stimulated innovative ideas and studies that expand the understanding of atomic and nuclear structure of heavy elements and of the interaction of nuclei with bound electrons and coherent light. Using the nuclear resonance frequency, determined by the strong and electromagnetic interactions inside the nucleus, it is possible to build a highly precise nuclear clock that will be fundamentally different from all other atomic clocks based on resonant frequencies of the electron shell. The nuclear clock will open opportunities for highly sensitive tests of fundamental principles of physics, particularly in searches for violations of Einstein’s equivalence principle and for new particles and interactions beyond the standard model. It has been proposed to use the nuclear clock to search for variations of the electromagnetic and strong coupling constants and for dark matter searches. The 229Th nuclear optical clock still represents a major challenge in view of the tremendous gap of nearly 17 orders of magnitude between the present uncertainty in the nuclear transition frequency (about 0.2 eV, corresponding to ∼48 THz) and the natural linewidth (in the mHz range). Significant experimental progress has been achieved in recent years, which will be briefly reviewed. Moreover, a research strategy will be outlined to consolidate our present knowledge about essential 229mTh properties, to determine the nuclear transition frequency with laser spectroscopic precision, realize different types of nuclear clocks and apply them in precision frequency comparisons with optical atomic clocks to test fundamental physics. Two avenues will be discussed: laser-cooled trapped 229Th ions that allow experiments with complete control on the nucleus–electron interaction and minimal systematic frequency shifts, and Th-doped solids enabling experiments at high particle number and in different electronic environments.

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Section: Solid-state-clock Operation and Performancementioning

confidence: 99%

Nuclear clocks for testing fundamental physics

Peik

Schumm

Safronova

et al. 2021

Quantum Sci. Technol.

Self Cite

109

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“…Even though the side reactions of Zn corrosion and HER are effectively suppressed as MgF 2 is an electrical insulator [ 31 , 32 ], an excessively thick passivation layer inhibits the diffusion of the Zn ions to the Zn metal anode. Therefore, the L-ZMF thickness on the Zn metal surface was optimized by varying the radio frequency sputtering time.…”

Section: Resultsmentioning

confidence: 99%

Stable Zn Metal Anodes with Limited Zn-Doping in MgF2 Interphase for Fast and Uniformly Ionic Flux

et al. 2022

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The practical applications of aqueous Zn metal batteries are currently restricted by the inherent drawbacks of Zn such as the hydrogen evolution reaction, sluggish kinetics, and dendrite formation. To address these problems, herein, a limitedly Zn-doped MgF2 interphase comprising an upper region of pure, porous MgF2 and a lower region of gradient Zn-doped MgF2 is achieved via radio frequency sputtering technique. The porous MgF2 region is a polar insulator whose high corrosion resistance facilitates the de-solvation of the solvated Zn ions and suppression of hydrogen evolution, resulting in Zn metal electrodes with a low interfacial resistance. The Zn-doped MgF2 region facilitates fast transfer kinetics and homogeneous deposition of Zn ions owing to the interfacial polarization between the Zn dopant and MgF2 matrix, and the high concentration of the Zn dopant on the surface of the metal substrate as fine nuclei. Consequently, a symmetric cell incorporating the proposed Zn metal exhibits low overpotentials of ~ 27.2 and ~ 99.7 mV without Zn dendrites over 250 to 8000 cycles at current densities of 1.0 and 10.0 mA cm−2, respectively. The developed Zn/MnO2 full cell exhibits superior capacity retentions of 97.5% and 84.0% with average Coulombic efficiencies of 99.96% after 1000 and 3000 cycles, respectively.

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“…This step is paramount for any nuclear clock, whether using trapped Th ions or Th-doped crystals. In the crystal environment, the 229 Th nuclei are subject to electric field gradients causing quadrupole splitting of the order of few hundred MHz [19,68]. In the absence of any external magnetic field, the quadrupole structure is degenerate with respect to the sign of projection of the nuclear angular momentum.…”

Section: A Eb Quenching Scheme and Nuclear Clock Performancementioning

confidence: 99%

Driven electronic bridge processes via defect states in $^{229}$Th-doped crystals

Nickerson,

Pimon,

Bilous

et al. 2021

Preprint

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The electronic defect states resulting from doping 229 Th in CaF2 offer a unique opportunity to excite the nuclear isomeric state 229m Th at approximately 8 eV via electronic bridge mechanisms. We consider bridge schemes involving stimulated emission and absorption using an optical laser. The role of different multipole contributions, both for the emitted or absorbed photon and nuclear transition, to the total bridge rates are investigated theoretically. We show that the electric dipole component is dominant for the electronic bridge photon. In contradistinction, the electric quadrupole channel of the 229 Th isomeric transition plays the dominant role for the bridge processes presented. The driven bridge rates are discussed in the context of background signals in the crystal environment and of implementation methods. We show that inverse electronic bridge processes quenching the isomeric state population can improve the performance of a solid-state nuclear clock based on 229m Th.

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DFT calculation of ²²⁹thorium-doped magnesium fluoride for nuclear laser spectroscopy

Cited by 17 publications

References 54 publications

Nuclear clocks for testing fundamental physics

Nuclear clocks for testing fundamental physics

Stable Zn Metal Anodes with Limited Zn-Doping in MgF2 Interphase for Fast and Uniformly Ionic Flux

Driven electronic bridge processes via defect states in $^{229}$Th-doped crystals

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DFT calculation of 229thorium-doped magnesium fluoride for nuclear laser spectroscopy

Cited by 17 publications

References 54 publications

Nuclear clocks for testing fundamental physics

Nuclear clocks for testing fundamental physics

Stable Zn Metal Anodes with Limited Zn-Doping in MgF2 Interphase for Fast and Uniformly Ionic Flux

Driven electronic bridge processes via defect states in $^{229}$Th-doped crystals

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DFT calculation of ²²⁹thorium-doped magnesium fluoride for nuclear laser spectroscopy