Evidence of Electronic Phase Separation in the Strongly Correlated Semiconductor YbB<sub>12</sub>
A. N. Azarevich, Н. Б. Болотина, О.Н. Хрыкина, A. V. Bogach, E. S. Zhukova, B. P. Gorshunov, Alexander Melentev, Z. V. Bedran, A. Alyabyeva, M. A. Belyanchikov, В. В. Воронов, N. Yu. Shitsevalova, В. Б. Филипов, N. E. Sluchanko
Abstract
We investigate high-quality single-domain crystals of YbB 12 using the precise x-ray diffraction technique in combination with the low-temperature polarized THz–infrared spectroscopy and accurate magnetotransport measurements. It is shown for the first time that this archetypal strongly correlated system with a metal-insulator transition to a mysterious dielectric ground state with a metal Fermi surface [ Science 362 , 65 (2018) and ibid 362 , 32 (2018)] is actually a heterogeneous compound in the regime of electronic phase separation. Changes in the configuration of the discovered dynamic charge stripes are proposed upon cooling. As a result, a conclusion is drawn in favor of a crossover between different patterns of the filamentary electronic structure penetrating the semiconducting matrix of YbB 12 . We argue that the discovery of stripes in YbB 12 is fundamental, elucidating the nature of exotic dielectric state in Kondo insulators.