Localization versus inhomogeneous superfluidity: Submonolayer He4 on fluorographene, hexagonal boron nitride, and graphene
نویسندگان
چکیده
We study a sub monolayer He-4 adsorbed on fluorographene (GF) and hexagonal boron nitride (hBN) at low coverage. The adsorption potentials have been computed ab-initio with suitable density functional theory including dispersion forces. properties of the atoms finite temperature path integral Monte Carlo T=0 K variational integral. From both methods we find that lowest energy state GF is superfluid. Due to very large corrugation potential this superfluid has strong spatial anisotropy, ratio between largest smallest areal being about 6, fraction T 55%, transition normal in range 0.5-1 K. Thus, offers platform for studying strongly interacting highly anisotropic bosonic At larger coverage an ordered commensurate occupation 1/6 sites. This phase stable up located 0.5 1~K. system triangular order similar graphite. hBN 1/3 sites symmetry. A disordered present lower as metastable state. In presence electric field slightly increased but magnitude 1 V/Ang. effect small does not change stability phases hBN. verified also case graphene such modify sqrt{3}*sqrt{3}R30 phase.
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ژورنال
عنوان ژورنال: Physical Review B
سال: 2021
ISSN: ['1098-0121', '1550-235X', '1538-4489']
DOI: https://doi.org/10.1103/physrevb.103.174514