Nayak Swagatam, Batra Navketan, Kumar Sanjeev
Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, PO 140306, Mohali, Manauli, India.
School of Physical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha, 752050, India.
Sci Rep. 2021 Nov 22;11(1):22724. doi: 10.1038/s41598-021-02175-5.
By introducing the possibility of equal- and opposite-spin pairings concurrently, we show that the ground state of the extended attractive Hubbard model (EAHM) exhibits rich phase diagrams with a variety of singlet, triplet, and mixed parity superconducting orders. We study the competition between these superconducting pairing symmetries invoking an unrestricted Hartree-Fock-Bogoliubov-de Gennes (HFBdG) mean-field approach, and we use the d-vector formalism to characterize the nature of the stabilized superconducting orders. We discover that, while all other types of orders are suppressed, a non-unitary triplet order dominates the phase space in the presence of an in-plane external magnetic field. We also find a transition between a non-unitary to unitary superconducting phase driven by the change in average electron density. Our results serve as a reference for identifying and understanding the nature of superconductivity based on the symmetries of the pairing correlations. The results further highlight that EAHM is a suitable effective model for describing most of the pairing symmetries discovered in different materials.
通过同时引入等自旋和反自旋配对的可能性，我们表明扩展吸引哈伯德模型（EAHM）的基态展现出具有各种单重态、三重态和混合宇称超导序的丰富相图。我们采用无限制的哈特里 - 福克 - 博戈留波夫 - 德热纳（HFBdG）平均场方法研究这些超导配对对称性之间的竞争，并使用d矢量形式来表征稳定的超导序的性质。我们发现，虽然所有其他类型的序都受到抑制，但在存在面内外部磁场的情况下，非幺正三重态序主导相空间。我们还发现由平均电子密度变化驱动的从非幺正到幺正超导相的转变。我们的结果为基于配对关联的对称性识别和理解超导性的本质提供了参考。结果进一步突出表明，EAHM是描述在不同材料中发现的大多数配对对称性的合适有效模型。
