Interplay between antiferrodistortive, ferroelectric, and superconducting instabilities in Sr1-x Ca-x TiO3-delta
Interplay between antiferrodistortive, ferroelectric, and superconducting instabilities in Sr1-x Ca-x TiO3-delta
复制标题
Sr1-x Ca-x TiO3-delta 中反铁畸变、铁电和超导不稳定性之间的相互作用
DOI：
10.1103/physrevb.91.045108
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发表时间：
2015
影响因子：
3.7
通讯作者：
K. Behnia
中科院分区：
文献类型：
--
作者：
B. S. de Lima;M. S. da Luz;F. S. Oliveira;L. M. S. Alves;C. A. M. dos Santos;F. Jomard;Y. Sidis;P. Bourges;S. Harms;C. P. Grams;J. Hemberger;X. Lin;B. Fauqué;K. Behnia
在105 K时经历了从α到四氢呋喃的相变。这种反铁畸变转变被认为是在竞争与初期铁电性。用等价钙取代锶诱导铁电有序。另一方面，通过化学非等价掺杂将移动的电子引入系统，导致具有超导基态的稀金属的出现。超导性和其他两种不稳定性之间的联系是一个在将非常规超导体和量子临界点联系起来的流行范式的背景下聚集动力的问题。我们提出了一套比热，中子散射，介电常数，极化测量和低温电导率的研究。钙的替代被发现，以提高反铁电畸变和铁电转变的转变温度。此外，我们还发现它是一个超导基态。在这种罕见的情况下，具有铁电母体的超导体的临界温度略低于具有可比载流子浓度的超导体。一个三维相图跟踪的三个转变温度的函数和结果从这项研究中，铁电和超导基态不是直接邻居。
undergoes a cubic-to-tetragonal phase transition at 105 K. This antiferrodistortive transition is believed to be in competition with incipient ferroelectricity. Substituting strontium by isovalent calcium induces a ferroelectric order. Introducing mobile electrons to the system by chemical nonisovalent doping, on the other hand, leads to the emergence of a dilute metal with a superconducting ground state. The link between superconductivity and the other two instabilities is a question gathering momentum in the context of a popular paradigm linking unconventional superconductors and quantum critical points. We present a set of specific-heat, neutron-scattering, dielectric-permittivity, and polarization measurements onand a study of low-temperature electric conductivity in. Calcium substitution was found to enhance the transition temperature for both antiferrodistortive and ferroelectric transitions. Moreover, we find thathas a superconducting ground state. The critical temperature in this rare case of a superconductor with a ferroelectric parent is slightly lower than inof comparable carrier concentration. A three-dimensional phase diagram fortracking the three transition temperatures as a function ofandresults from this study, in which ferroelectric and superconducting ground states are not immediate neighbors.