论文标题
Valleytronic材料的建议：Ferrovalley Metal和Valley Gapless Seconconductor
Proposal for valleytronic materials: ferrovalley metal and valley gapless semiconductor
论文作者
论文摘要
Valleytronic材料可以为未来的电子设备提供新的自由度。 In this work, the concepts of the ferrovalley metal (FVM) and valley gapless semiconductor (VGS) are proposed, which can be achieved in valleytronic bilayer systems by electric-field tuning, where the interaction between out-of-plane ferroelectricity and A-type antiferromagnetism can induce layer-polarized anomalous valley Hall (LP-AVH) effect. FVM的K和-K山谷既是金属，又存在电子和孔载体。在极端情况下，FVM可以通过类似于自旋空隙半导体（SG）来成为VG。此外，有人提出，Valleytronic Biilayer系统中的电场可以实现山谷分裂的增强和山谷极化的逆转。以BiLayer $ \ mathrm {Rubr_2} $为例，我们的建议是通过第一原则计算确认的。通过应用电场，可以在双层$ \ mathrm {rubr_2} $中实现FVM和VGS。在适当的电场范围内，增加电场可以增强山谷的分裂，并且可以通过翻转电场方向来逆转山谷极化。为了有效地通过双层系统中的电场来调整谷地的特性，母体单层应具有平面外磁化，并具有较大的山谷分裂。我们的结果阐明了电场在调整Valleytronic双层系统中的可能作用，并提供了一种通过电场设计与Ferrovalley相关的材料的方法。
Valleytronic materials can provide new degrees of freedom to future electronic devices. In this work, the concepts of the ferrovalley metal (FVM) and valley gapless semiconductor (VGS) are proposed, which can be achieved in valleytronic bilayer systems by electric-field tuning, where the interaction between out-of-plane ferroelectricity and A-type antiferromagnetism can induce layer-polarized anomalous valley Hall (LP-AVH) effect. The K and -K valleys of FVM are both metallic, and electron and hole carriers simultaneously exist. In the extreme case, the FVM can become VGS by analogizing spin gapless semiconductor (SGS). Moreover, it is proposed that the valley splitting enhancement and valley polarization reversal can be achieved by electric field in valleytronic bilayer systems. Taking the bilayer $\mathrm{RuBr_2}$ as an example, our proposal is confirmed by the first-principle calculations. The FVM and VGS can be achieved in bilayer $\mathrm{RuBr_2}$ by applying electric field. With appropriate electric field range, increasing electric field can enhance valley splitting, and the valley polarization can be reversed by flipping electric field direction. To effectively tune valley properties by electric field in bilayer systems, the parent monolayer should possess out-of-plane magnetization, and have large valley splitting. Our results shed light on the possible role of electric field in tuning valleytronic bilayer systems, and provide a way to design the ferrovalley-related material by electric field.
