3D Plot from Scientific Research

Anisotropic Coulomb potential (grey surface) of the excitons. The isoenergy contours (white ellipses) and the projections (black lines) onto the two crystallographic directions highlight the large in-plane anisotropy. Although the a and b axes share a common 1 s level (light grey line), the degeneracy of the 2 p states is lifted. Consequently, the 1 s 2 p a and 1 s 2 p b transitions (vertical red lines) feature different energies that are interrogated by MIR transients (red waveforms) of orthogonal polarization ( E MIR || a and E MIR || b , respectively).

DOI