Dresden 2020 – wissenschaftliches Programm
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TT 17.4: Poster
Montag, 16. März 2020, 15:00–19:00, P2/EG
Scanning Tunneling Microscopy on Eu5In2Sb6: a non-symmorphic antiferromagnetic insulator — •Maria Victoria Ale Crivillero1, Sahana Roessler1, Priscila F. S. Rosa2, and Steffen Wirth1 — 1Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany. — 2Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Motivated by theoretical predictions of non-trivial Fermi surface topology stabilized by the non-symmorphic symmetry in the Zintl phase Ba5In2Sb6, we investigated the magnetic analogue Eu5In2Sb6. The inclusion of Eu gives rise to a complex magnetic behavior. At low temperatures, two magnetic transitions (TN1≈14 K and TM2≈7 K), revealed in our magnetization, heat-capacity and transport measurements, point to such an intricate magnetic structure. Interestingly, the emergence of colossal magnetoresistance (CMR) suggests the formation of magnetic polarons.
We performed complementary STM/STS measurements. To this end, we attempted to cleave the samples in situ in UHV and at low temperatures along the a, b and c-axis. Eu5In2Sb6 crystallizes in an orthorhombic structure (Pbam), characterized by infinite [In2Sb6]10− double chains along the c-axis. In the (010) plane, we obtained striped patterns that can be correlated to the double-chains stacking. The attempted cleavage along the a-axis revealed a more complex pattern, which could be indicative of cleavage along the (110) plane. So far, no clear experimental evidence of surface states was observed.