The recently discovered ${\mathrm{LaFe}}_2{\mathrm{As}}_2$ superconducting compound, member of the 122 family of iron pnictide superconductors, becomes superconducting below $T_c\approx 13\mathrm{K}$, yet its nominal doping apparently places it in the extreme overdoped limit, where superconductivity should be suppressed. In this work, we investigate the normal state of magneto- and thermoelectric transport and specific heat of this compound. The experimental data are consistent with the presence of highly compensated electron and hole bands, with ∼0.42 electrons per unit cell just above $T_{\mathrm{c}}$, and high effective masses $\sim 3m_0$. The temperature dependence of transport properties strongly resembles that of conventional superconductors, pointing to a key role of electron-phonon coupling. From this evidence, ${\mathrm{LaFe}}_2{\mathrm{As}}_2$ can be regarded as the connecting compound between unconventional and conventional superconductors.

中文翻译：

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未塌陷的LaFe2As2相：补偿，高掺杂，电子声子耦合的铁基超导体

最近发现 ${\mathrm{镧铁}}_2{\mathrm{如}}_2$ 超导电化合物，是铁素体铁超导体122家族的成员，在以下温度超导 ${Ť}_C\approx 13\mathrm{ķ}$但是，其标称掺杂显然将其置于极端超掺杂极限中，在该极限中应抑制超导性。在这项工作中，我们研究了该化合物的磁电和热电传输的正常状态以及比热。实验数据与高度补偿的电子和空穴带的存在一致，每单位晶胞约有0.42个电子${Ť}_{\mathrm{C}}$和高有效质量 $〜3{米}_0$。传输特性的温度依赖性与常规超导体的温度依赖性非常相似，指出了电子-声子耦合的关键作用。从这个证据来看，${\mathrm{镧铁}}_2{\mathrm{如}}_2$ 可以被视为非常规和常规超导体之间的连接化合物。