Quantum Critical Origin of the Superconducting Dome in SrTiO3
Quantum Critical Origin of the Superconducting Dome in SrTiO3
复制标题
DOI：
10.1103/physrevlett.115.247002
复制
发表时间：
2015-12-10
影响因子：
8.6
通讯作者：
Balatsky, Alexander V.
中科院分区：
文献类型：
--
作者：
Edge, Jonathan M.;Kedem, Yaron;Balatsky, Alexander V.
我们扩展了众所周知的概念，量子临界性可以诱导超导性，提出了一个具体的机制，超导性由于量子铁电涨落。为此，我们调查的起源掺杂SrTiO 3的超导电性使用的密度泛函和强耦合理论的量子临界性的框架内的组合。我们的密度泛函计算的铁电体软模频率作为掺杂的函数揭示了一个交叉相关的量子顺电在掺杂水平与实验观察到的超导圆顶的顶部相一致。因此，我们提出了一个模型，其中软模涨落提供了超导载流子的配对相互作用。在我们的模型中，超导圆顶的低掺杂极限是由费米面的出现来解释的，而高掺杂极限是由量子临界区的偏离来解释的。我们预测，最高的临界温度将增加和转移到较低的载流子掺杂增加O-18同位素取代，一种情况下，是实验验证。我们的模型也适用于其他量子顺电体，如KTaO 3。
We expand the well-known notion that quantum criticality can induce superconductivity by proposing a concrete mechanism for superconductivity due to quantum ferroelectric fluctuations. To this end, we investigate the origin of superconductivity in doped SrTiO3 using a combination of density functional and strong coupling theories within the framework of quantum criticality. Our density functional calculations of the ferroelectric soft mode frequency as a function of doping reveal a crossover related to quantum paraelectricity at a doping level coincident with the experimentally observed top of the superconducting dome. Thus, we suggest a model in which the soft mode fluctuations provide the pairing interaction for superconductivity carriers. Within our model, the low doping limit of the superconducting dome is explained by the emergence of the Fermi surface, and the high doping limit by departure from the quantum critical regime. We predict that the highest critical temperature will increase and shift to lower carrier doping with increasing O-18 isotope substitution, a scenario that is experimentally verifiable. Our model is applicable to other quantum paraelectrics, such as KTaO3.