Single-Spin Dirac Fermion and Chern Insulator Based on Simple Oxides

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• 作者：Tianyi Cai ; Xiao Li ; Fa Wang ; Sheng Ju ; Ji Feng ; Chang-De Gong
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：6434-6439
• 全文大小：378K
• ISSN：1530-6992

文摘

It is highly desirable to combine recent advances in the topological quantum phases with technologically relevant materials. Chromium dioxide (CrO₂) is a half-metallic material, widely used in high-end data storage applications. Using first-principles calculations, we show that a novel class of half semimetallic Dirac electronic phase emerges at the interface CrO₂ with TiO₂ in both thin film and superlattice configurations, with four spin-polarized Dirac points in momentum-space (k-space) band structure. When the spin and orbital degrees of freedom are allowed to couple, the CrO₂/TiO₂ superlattice becomes a Chern insulator without external fields or additional doping. With topological gaps equivalent to 43 K and a Chern number 卤2, the ensuing quantization of Hall conductance to 卤2e²/h will enable potential development of these highly industrialized oxides for applications in topologically high fidelity data storage and energy-efficient electronic and spintronic devices.