Anisotropy in the upper critical field of FeSe and FeSe0.33Te0.67 single crystalsстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 5 мая 2015 г.
Аннотация:The electric resistivity of single crystalline Fe-based superconductors FeSe and FeSe0.33Te0.67
was measured in pulsed magnetic fields up to 55 T. Te-doped iron selenide, FeSe0.33Te0.67,
shows rather isotropic behavior in both magnetoresistance (MR) and upper critical fields ( ⊥ Hc2(0)/
∥ Hc2(0) = 48 T/ 42 T ∼ 1.14), when an external magnetic field is applied parallel and
perpendicular to the crystallographic c-axis. These isotropic behaviors are frequently observed in
an iron-based superconductor, and the isotropy in Hc2 can likely be described by the Pauli effect.
In contrast, our measurements elucidate that the undoped iron selenide, FeSe, exhibits a clear
anisotropy in both MR and Hc2 ( ⊥ Hc2(0)/ ∥ Hc2(0) = 27 T/ 15 T ∼ 1.8). This behavior occurs because
the clean in-plane conduction (RRR = 35) allows to form a closed electron orbit within the twodimensional
Fermi sheets only for the magnetic field parallel to the c-axis, which results in an
appearance of an intrinsic (orbital-effect limited) upper critical field for the undoped FeSe.
Doping of Te breaks the clean in-plane conduction and leads to a crossover from an orbital limit
dominating behavior to a Pauli limit dominating one.