Polarity reversal of the charge carrier in tetragonal TiHx(x=1.6-2.0) at low temperatures
Polarity reversal of the charge carrier in tetragonal TiHx(x=1.6-2.0) at low temperatures
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低温下四方TiHx(x=1.6-2.0)载流子的极性反转
DOI：
10.1103/physrevresearch.2.033467
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发表时间：
2020
影响因子：
4.2
通讯作者：
Hitosugi Taro
中科院分区：
文献类型：
--
作者：
Shimizu Ryota;Sasahara Yuki;Hamada Ikutaro;Oguchi Hiroyuki;Ogura Shohei;Shirasawa Tetsuroh;Kitamura Miho;Horiba Koji;Kumigashira Hiroshi;Orimo Shin-ichi;Fukutani Katsuyuki;Hitosugi Taro
本文对外延薄膜的电荷输运性质进行了理论和实验相结合的研究。我们发现，的霍尔系数强烈地依赖于氢含量和晶胞体积：接近化学计量的薄膜与大晶胞体积显示在4 K的正霍尔系数，而样品与小晶胞体积显示在4 K的负霍尔系数。我们的密度泛函理论计算表明，体积的变化导致的四方晶格的纵横比的变化，从而解除Ti态的简并，并改变费米面的电子和空穴的贡献和霍尔系数的符号。本研究阐明了晶格对称性在决定电荷载流子极性方面的重要作用，我们认为，可以通过晶格参数通过氢含量来调节金属氧化物的电子性质。
We present a combined experimental and theoretical study of the charge transport properties ofepitaxial thin films. We found that the Hall coefficient ofstrongly depends on hydrogen content and unit-cell volume: Nearly stoichiometricfilms with large unit-cell volumes showed positive Hall coefficients at 4 K, whereassamples withand small unit-cell volumes showed negative Hall coefficients at 4 K. Our density functional theory calculations reveal that the volume change leads to the change in the aspect ratio of the tetragonal lattice, thereby lifting the degeneracy of Tistates, and alters the contributions of electrons and holes at the Fermi surface and the sign of the Hall coefficient. The present study clarifies the important role of the lattice symmetry in determining the charge carrier polarity, and we suggest that electronic properties of metal hydrides can be tuned by the lattice parameters via the hydrogen contents.