Emergence of Two-Dimensional Massless Dirac Fermions, Chiral Pseudospins, and Berry鈥檚 Phase in Potassium Doped Few-Layer Black Phosphorus

详细信息    查看全文

• 作者：Seung Su Baik ; Keun Su Kim ; Yeonjin Yi ; Hyoung Joon Choi
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：7788-7793
• 全文大小：465K
• ISSN：1530-6992

文摘

Thin flakes of black phosphorus (BP) are a two-dimensional (2D) semiconductor whose energy gap is predicted being sensitive to the number of layers and external perturbations. Very recently, it was found that a simple method of potassium (K) doping on the surface of BP closes its band gap completely, producing a Dirac semimetal state with a linear band dispersion in the armchair direction and a quadratic one in the zigzag direction. Here, based on first-principles density functional calculations, we predict that, beyond the critical K density of the gap closure, 2D massless Dirac Fermions (i.e., Dirac cones) emerge in K-doped few-layer BP, with linear band dispersions in all momentum directions, and the electronic states around Dirac points have chiral pseudospins and Berry鈥檚 phase. These features are robust with respect to the spin鈥搊rbit interaction and may lead to graphene-like electronic transport properties with greater flexibility for potential device applications.