Single crystal growth, transport and scanning tunneling microscopy and spectroscopy of FeSe1-xSxстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 10 августа 2018 г.
Аннотация:Single crystals of sulfur‐substitued iron selenide, FeSe1‐xSx, were grown within eutectics of molten halides, AlCl3/KCl, AlCl3/KCl/NaCl or AlCl3/KBr, at permanent temperature gradient. The innovative “ampoule in ampoule” design of a crystallization vessel allows obtaining the mm‐sized plate‐like single crystals with the sulfur content up to x ~ 0.19. The sharp anomalies in physical properties mark the superconducting at TC = 8.4 K and nematic at TN = 90 K phase transitions in FeSe0.96. Scanning tunneling microscopy reveals presence of dumbbell defects associated with Fe vacancies and dark defects at the chalcogen site associated to S within FeSe1-xSx series of compounds. Scanning tunneling spectroscopy shows the presence of two different superconducting gaps at both hole and electron pockets of Fermi surface for low level of S content. As a function of sulfur content, TC follows the conventional dome‐shaped curve while TN decreases with x. The overall appearance of T ‐ x phase diagram in FeSe1‐xSx suggests the importance of nematic fluctuations for the formation of superconducting state in thes compounds.