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We present a novel scenario, in which light ($\sim$ few \rm{eV}) darkfermions (sterile neutrinos) interact with a scalar field like in mass varyingneutrino dark energy theories. As the $\rm{eV}$ sterile states naturally becomenon-relativistic before the Matter Radiation Equality (MRE), we show that theneutrino-scalar fluid develops strong perturbative instability followed by theformation of neutrino-nuggets and the early dark energy behaviour disappearsaround MRE. The stability of the nugget is achieved when the Fermi pressurebalances the attractive scalar force and we numerically find the mass andradius of heavy cold nuggets by solving for the static configuration for thescalar field. We find that for the case when DM nugget density is sub-dominantand most of the early DE energy goes into scalar field dynamics, it can inprinciple relax the Hubble anomaly. Especially when a kinetic energy dominatedphase appears after the phase transition, the DE density dilutes faster thanradiation and satisfy the requirements for solving $H_0$ anomaly. In ourscenario, unlike in originally proposed early dark energy theory, the darkenergy density is controlled by ($\rm{eV}$) neutrino mass and it does notrequire a fine tuned EDE scale. We perform a MCMC analysis and confront ourmodel with Planck + SHOES and BAO data and find an evidence for non-zeroneutrino-scalar EDE density during MRE. Our analysis shows that this model isin agreement of nearly 1.3$\sigma$ with SHOES measurement which is $H_0 = 74.03\pm 1.42$ km/s/Mpc.

Early mass varying neutrino dark energy: Nugget formation and Hubble anomaly