Direct measurement of ferroelectric polarization in a tunable semimetal.
Direct measurement of ferroelectric polarization in a tunable semimetal.
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DOI：
10.1038/s41467-021-25587-3
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发表时间：
2021-09-06
影响因子：
16.6
通讯作者：
Hunt BM
中科院分区：
文献类型：
--
作者：
de la Barrera SC;Cao Q;Gao Y;Gao Y;Bheemarasetty VS;Yan J;Mandrus DG;Zhu W;Xiao D;Hunt BM
铁电性是铁磁性的静电对应物，长期以来一直被认为与金属性不相容，因为电偶极子和外部电场被巡回电荷屏蔽。然而，最近的测量表明，在双层和三层的WTe2，半金属过渡金属二硫属化物与破反转对称的电导铁电开关的签名。该系统的一个特别有前途的方面是，电子和空穴的密度可以通过外部栅极电压连续调谐。这种自由度使得能够在自由载流子被添加到系统时测量自发极化。在这里，我们采用电容传感在双层WTe2的双栅介观器件直接测量在金属状态下的自发极化和量化的传导和价带中的极化，分别自由载流子的影响。我们比较我们的结果的低能量模型的电子带，并确定层极化状态，有助于运输和极化的同时。因此，双层WTe2被证明是一个完全可调的铁电金属和探索极性排序，铁电转换，和应用程序中存在的自由载流子的理想平台。铁电金属中自由载流子与电极化共存。在这里，作者使用电容的方法来探测可调半金属中的自由载流子的电子压缩性，提取极化贡献，并研究铁电态的载流子依赖性。
Ferroelectricity, the electrostatic counterpart to ferromagnetism, has long been thought to be incompatible with metallicity due to screening of electric dipoles and external electric fields by itinerant charges. Recent measurements, however, demonstrated signatures of ferroelectric switching in the electrical conductance of bilayers and trilayers of WTe2, a semimetallic transition metal dichalcogenide with broken inversion symmetry. An especially promising aspect of this system is that the density of electrons and holes can be continuously tuned by an external gate voltage. This degree of freedom enables measurement of the spontaneous polarization as free carriers are added to the system. Here we employ capacitive sensing in dual-gated mesoscopic devices of bilayer WTe2 to directly measure the spontaneous polarization in the metallic state and quantify the effect of free carriers on the polarization in the conduction and valence bands, separately. We compare our results to a low-energy model for the electronic bands and identify the layer-polarized states that contribute to transport and polarization simultaneously. Bilayer WTe2 is thus shown to be a fully tunable ferroelectric metal and an ideal platform for exploring polar ordering, ferroelectric transitions, and applications in the presence of free carriers. Free carriers and electrical polarization coexist in ferroelectric metals. Here, the authors use a capacitive method to probe the electronic compressibility of free carriers in a tunable semimetal, extract the polarized contribution, and study the carrier dependence of the ferroelectric state.
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影响因子：
16.6
作者：
Woods CR;Ares P;Nevison-Andrews H;Holwill MJ;Fabregas R;Guinea F;Geim AK;Novoselov KS;Walet NR;Fumagalli L
通讯作者：
Fumagalli L
双层 WTe2 中强非线性霍尔效应的能带特征
影响因子：
8.6
作者：
Du, Z. Z.;Wang, C. M.;Xie, X. C.
通讯作者：
Xie, X. C.
影响因子：
10.8
作者：
Telford, Evan J.;Benyamini, Avishai;Hone, James
通讯作者：
Hone, James
影响因子：
29.4
作者：
Liebmann, Marcus;Rinaldi, Christian;Morgenstern, Markus
通讯作者：
Morgenstern, Markus
影响因子：
16.6
作者：
Hunt BM;Li JIA;Zibrov AA;Wang L;Taniguchi T;Watanabe K;Hone J;Dean CR;Zaletel M;Ashoori RC;Young AF
通讯作者：
Young AF