Discovery of Weyl semimetal TaAs
Discovery of Weyl semimetal TaAs
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2015-02
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通讯作者：
B. Lv;H. Weng;B. Fu;X. P. Wang;H. Miao;Junzhang Ma;P. Richard;Xiaochun Huang;Lingxiao Zhao;Genfu Chen;Z. Fang;X. Dai;T. Qian;H. Ding
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作者：
B. Lv;H. Weng;B. Fu;X. P. Wang;H. Miao;Junzhang Ma;P. Richard;Xiaochun Huang;Lingxiao Zhao;Genfu Chen;Z. Fang;X. Dai;T. Qian;H. Ding
Weyl半金属是最近预测的一类材料，可以被视为石墨烯破坏时间反转或反转对称的三维类似物。外尔半金属中的电子表现为外尔费米子，它具有许多奇异的性质，如手征反常和晶体动量空间中的磁单极。外尔半金属的表面态在两个相对的表面上显示出一对纠缠的费米弧。然而，外尔半金属的存在尚未得到实验证明。在这里，我们报告的实验实现的Weyl半金属TaAs通过观察费米弧形成的表面状态，使用角分辨光电子能谱。我们的第一性原理计算，匹配非常好的实验结果，进一步证实了TaAs是外尔半金属。
Weyl semimetals are recently predicted class of materials that can be regarded as three-dimensional analogs of graphene breaking time reversal or inversion symmetry. Electrons in a Weyl semimetal behave as Weyl fermions, which have many exotic properties, such as chiral anomaly and magnetic monopoles in the crystal momentum space. The surface state of a Weyl semimetal displays pairs of entangled Fermi arcs at two opposite surfaces. However, the existence of Weyl semimetals has not yet been proved experimentally. Here we report the experimental realization of a Weyl semimetal in TaAs by observing Fermi arcs formed by its surface states using angle-resolved photoemission spectroscopy. Our first-principles calculations, matching remarkably well with the experimental results, further confirm that TaAs is a Weyl semimetal.