Superconductivity in electron-doped layered TiNCl with variable interlayer coupling
Superconductivity in electron-doped layered TiNCl with variable interlayer coupling
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DOI：
10.1103/physrevb.86.024516
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发表时间：
2012-07
影响因子：
3.7
通讯作者：
Shuai Zhang;Masashi Tanaka;S. Yamanaka
中科院分区：
文献类型：
--
作者：
Shuai Zhang;Masashi Tanaka;S. Yamanaka
氮化钛(TiNCl)是一种具有层状结构的能带半导体，通过碱金属插层掺杂电子使其成为转变温度为18.0K的超导体。当各种有机溶剂分子与碱原子共插层时，超导层状晶体会发生不同程度的膨胀，并随着分子的大小而线性下降到6.5K，其中$d$是扩展的氮化物层的层间距(层间距)，这意味着库仑层间耦合对超导电性的重要性。这与以前的研究结果形成了鲜明的对比，在类似的溶剂分子共插层作用下，具有层状结构的电子掺杂的ZrNCl和HfNCl的{T}_c}随着$d$的增加而增加。
Titanium nitride chloride (TiNCl), a band semiconductor with the $\ensuremath{\alpha}$-form layered structure, becomes a superconductor with a transition temperature ${T}_{c}\ensuremath{\approx}$ 18.0 K by electron doping via alkali-metal intercalation. Upon cointercalation of various kinds of organic solvent molecules with alkali atoms, the superconducting layered crystals are swelled to different extents adjusting to the size of the molecules, and the ${T}_{c}$ decreases linearly down to 6.5 K as a function of 1/$d$, where $d$ is the interlayer separation (basal spacing) of the expanded nitride layers, implying the importance of the Coulomb interlayer coupling for superconductivity. This is in strong contrast to a previous finding that the ${T}_{c}$ of the electron-doped ZrNCl and HfNCl with the $\ensuremath{\beta}$-form layered structure rather increases with the increase of $d$ upon a similar cointercalation of solvent molecules.