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TT: Fachverband Tiefe Temperaturen
TT 20: Cryotechnique & Measuring Devices: Poster Session
TT 20.4: Poster
Monday, March 7, 2016, 15:00–18:00, Poster D
Experimental aspects of the specific heat of superconductors derived from topological insulators — •Lionel Andersen, Oliver Breunig, Thomas Lorenz, and Yoichi Ando — II. Physikalisches Institut - Universität zu Köln, Germany
The expectation for topological superconductors to have an unconventional pairing symmetry makes them promising hosts for Majorana fermions. Recently the topological insulators Bi2Se3 (BS) and (PbSe)5(Bi2Se3)6 (PSBS) were reported to become superconducting when intercalating them with copper [1, 2]. Literature data of specific heat on both, CuxBS and CuxPSBS, indicate an unusual temperature dependence not described by standard BCS theory [2, 3]. This makes them promising candidates of topological superconductors but in order to clarify these issues it is necessary to perform cp measurements below 250 mK using a 3He/4He dilution cryostat. Because cp of superconductors becomes very small far below Tc the addendum contribution of the setup has to be minimized.
This demand together with other complications e.g. nuclear Schottky contributions to cp, leads to a drastic increase of the experimental effort. In this contribution experimental aspects of cp measurements with respect to the topological superconductor materials will be discussed in detail.
[1] Y. S. Hor et al., PRL 104 057001 (2010)
[2] Y. Ando et al., PRB 90 220504 (2014)
[3] Y. Ando et al., PRL 106 127004 (2011)