This content will become publicly available on June 17, 2023
 Award ID(s):
 2004420
 Publication Date:
 NSFPAR ID:
 10334666
 Journal Name:
 ACS Nano
 ISSN:
 19360851
 Sponsoring Org:
 National Science Foundation
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Two dimensional (2D) materials such as graphene and transition metal dichalcogenides (TMDs) are promising for optical modulation, detection, and light emission since their material properties can be tuned ondemand via electrostatic doping1–21. The optical properties of TMDs have been shown to change drastically with doping in the wavelength range near the excitonic resonances22–26. However, little is known about the effect of doping on the optical properties of TMDs away from these resonances, where the material is transparent and therefore could be leveraged in photonic circuits. Here, we probe the electrooptic response of monolayer TMDs at near infrared (NIR) wavelengths (i.e. deep in the transparency regime), by integrating them on silicon nitride (SiN) photonic structures to induce strong light matter interaction with the monolayer. We dope the monolayer to carrier densities of (7.2 ± 0.8) × 1013 cm2, by electrically gating the TMD using an ionic liquid [P14+] [FAP]. We show strong electrorefractive response in monolayer tungsten disulphide (WS2) at NIR wavelengths by measuring a large change in the real part of refractive index ∆n = 0.53, with only a minimal change in the imaginary part ∆k = 0.004. We demonstrate photonic devices based on electrostatically gated SiNWS2 phase modulator withmore »

The Kitaev honeycomb model has attracted significant attention due to its exactly solvable spinliquid ground state with fractionalized Majorana excitations and its possible materialization in magnetic Mott insulators with strong spinorbit couplings. Recently, the 5delectron compound H3LiIr2O6 has shown to be a strong candidate for Kitaev physics considering the absence of any signs of a longrange ordered magnetic state. In this work, we demonstrate that a finite density of random vacancies in the Kitaev model gives rise to a striking pileup of lowenergy Majorana eigenmodes and reproduces the apparent powerlaw upturn in the specific heat measurements of H3LiIr2O6. Physically, the vacancies can originate from various sources such as missing magnetic moments or the presence of nonmagnetic impurities (true vacancies), or from local weak couplings of magnetic moments due to strong but rare bond randomness (quasivacancies). We show numerically that the vacancy effect is readily detectable even at low vacancy concentrations and that it is not very sensitive either to the nature of vacancies or to different flux backgrounds. We also study the response of the sitediluted Kitaev spin liquid to the threespin interaction term, which breaks timereversal symmetry and imitates an external magnetic field. We propose a fieldinduced fluxsector transitionmore »

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Abstract The bonddisordered Kitaev model attracts much attention due to the experimental relevance in
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