Modification of the synthesis of layered titanium chloride nitride
Modification of the synthesis of layered titanium chloride nitride
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DOI：
10.1016/j.materresbull.2022.111896
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发表时间：
2022-06-02
影响因子：
5.4
通讯作者：
Yokoya，Takayoshi
中科院分区：
文献类型：
--
作者：
Tanaka，Masashi;Kataoka，Noriyuki;Yokoya，Takayoshi
层状氮化钛具有较高的超导转变温度(∼16K)，是非常规超导体的候选材料。为了更好地理解超导电性，我们对TiNCl的合成工艺进行了改进。采用化学气相传输法在不同的传输温度下制备了高结晶度的TiNCl2，并与金属钠(Na)进行了插层。虽然Rietveld精修得到的晶体参数相似，但超导性能强烈地依赖于原始TiNCl的处理温度。光学和光电子能谱显示，在费米能级以下存在带隙状态，这表明氢的掺入，这与β−的情况类似。氢气程序升温脱附发现，与热处理得到的纯净TiNCl2相比，氢气的释放很少。氢的带隙状态抑制了电子载流子从插层金属钠中的引入。
Layered titanium nitride chloride (TiNCl) exhibits a relatively high superconducting transition of ∼16 K, and it is a candidate for the unconventional superconductor. To better understand the superconductivity, we modified the synthesis process for TiNCl. Highly crystalline TiNCl was prepared by chemical vapor transport at different transport temperatures and intercalated with sodium (Na) metal. Although the crystallographic parameters obtained through Rietveld refinement are similar, the superconducting properties strongly depend on the treatment temperature of pristine TiNCl. Optical and photoemission spectroscopy revealed an in-gap state below the Fermi level, indicating hydrogen incorporation, similar to the case of β−ZrNCl. Hydrogen temperature-programmed desorption revealed hydrogen emission against the heat treatment of the obtained pristine TiNCl. The in-gap state of hydrogen inhibits the introduction of electron carriers from the intercalated Na metal.