Page curves of Reissner–Nordström black hole in HD gravity

We obtain the Page curves of an eternal Reissner-Nordstr\"om black hole in presence higher derivative terms four dimensions. consider two cases: gravitational action with general ${\cal O}(R^2)$ plus Maxwell term and Einstein-Gauss-Bonnet gravity term. In both cases entanglement entropy Hawking radiation absence island surface is increasing linearly time. After including contribution from surface, we find that after time, reaches a constant value which twice Bekenstein-Hawking curves. appear at later or earlier time when Gauss-Bonnet coupling increases decreases. Further, scrambling decreasing depending upon whether correction (coming action) first case whereas remains unaffected second (Einstein-Gauss-Bonnet case). As consistency check, limit vanishing GB curve obtained arXiv:2101.06867.