[en] Complete text of publication follows. The ¹¹Be nucleus is understood to have an one-neutron halo due to the small binding energy (0.5 MeV) from the lowest threshold of ¹⁰Be + n. The order of this weakly binding ground state (J^π = 1/2⁺) and the first excited state (0.18 MeV; J^π = 1/2^-) can not be understood in the framework of the naive shell model, where the ground state is predicted to be 1/2^-, but 1/2⁺ is assigned to an excited state. This parity inversion problem has a long history since Talmi and Unna pointed out in 1960 (1). This parity inversion phenomena have been studied by taking into account the coupling of a valence neutron with the deformed ¹⁰Be core (2). Furthermore, in addition to the deformation of the ¹⁰Be core, the pairing blocking effect was discussed to give a contribution to the inversion (3). Recently, the pairing blocking effect was shown to play a definitely important role in appearance of the virtual s-wave resonance in ¹⁰Li, which is an essential constituent of the halo nucleus ¹¹Li (4). We study the ¹¹Be nucleus using a semi-microscopic ¹⁰Be + n model. In order to take into account the coupling between the degree of freedom of the ¹⁰Be core and the valence neutron motion, we express the ¹⁰Be core wave function with the SU(3)(2,2)+pairing configurations. The Pauli principle between the ¹⁰Be core and the valence neutron is taken exactly by the orthogonality condition model. We discuss the structure of the ¹¹Be low-energy spectrum by solving the coupled channel problem of ¹⁰Be + n, where the resonant states together with the bound states are solved by applying the complex scaling method. The coupling of the ¹⁰Be core deformation and the valence neutron shows to reproduce the level inversion of 1/2⁺ and 1/2^- states. The other excited levels are calculated simultaneously, and it is found that the positive parity states (1/2⁺, 3/2⁺, 5/2⁺) are well reproduced. But the negative parity states (1/2^-, 3/2^-, 5/2^-) are not so good, especially the 5/2^- state is much lower than the experimental data. With decreasing the coupling between the core deformation and a valence neutron, and introducing the pairing excitation of the ¹⁰Be core, the negative parity levels of the ¹¹Be nucleus are much improved. With calculation of other physical quantities (rms, E1, etc.), we show that we can get a unified understanding of the ¹¹Be low-energy structure from the pint of view of the ¹⁰Be + n model including deformation and pairing correlations. (author)