Bipolar Magnetic and Thermospin Transport Properties of Graphene Nanoribbons with Zigzag and Klein Edges

Xingyi Tan,Gang Xu,Dahua Ren,Youchang Jiang,Georgios I Giannopoulos

doi:10.1155/2021/1792405

Abstract

Magnetic nanoribbons based on one-dimensional materials are potential candidates for spin caloritronics devices. Here, we constructed ferromagnetic graphene nanoribbons with zigzag and Klein edges (N-ZKGNRs, N = 4–21) and found that the N-ZKGNRs are in the indirect-gap bipolar magnetic semiconducting state (BMS). Moreover, when a temperature difference is applied through the nanoribbons, spin-dependent currents with opposite flow directions and opposite spin directions are generated, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). In addition, the spin-dependent Seebeck diode effect (SDSD) also appeared in these devices. More importantly, we found that the BMS with a larger bandgap is promising for generating the SDSD, while the BMS with a smaller bandgap is promising for generating the SDSE. These findings show that ZKGNRs are promising candidates for spin caloritronics devices.

Highlights

Spin caloritronics, which focuses on the interaction between the spin, charge, and heat in materials, has attracted intensive interest because it plays an important role in the development of fundamental science and novel low-powerconsumption technologies [1,2,3,4,5,6]
We found that ZKGNRs can be used in the stable bipolar magnetic semiconductor [19,20,21], in which the valence bands and conduction bands approach the Fermi level through opposite spin channels, and the spin-dependent Seebeck effect (SDSE) can be obtained. e results indicate that ZKGNRs are promising for application in spin caloritronics devices
For N 6, the conduction band minimum (CBM) is related to the spindown states and located at the Γ point, and the spin-up states below EF serve as the valence band maximum (VBM) and are located at the Γ–Z line

Summary

Introduction

Spin caloritronics, which focuses on the interaction between the spin, charge, and heat in materials, has attracted intensive interest because it plays an important role in the development of fundamental science and novel low-powerconsumption technologies [1,2,3,4,5,6] In this field, an important effect is the spin-dependent Seebeck effect (SDSE) [7,8,9], which features different Seebeck thermopowers for different spins in spin-polarized systems. We observed the SDSE in GNRs and silicene nanoribbons (SiNRs) with armchair or zigzag edges [12,13,14]. We found that ZKGNRs can be used in the stable bipolar magnetic semiconductor [19,20,21], in which the valence bands and conduction bands approach the Fermi level through opposite spin channels, and the SDSE can be obtained. e results indicate that ZKGNRs are promising for application in spin caloritronics devices

Methods

Results

Conclusion