Significant Increase of Electron Thermal Conductivity in Dirac Semimetal Beryllonitrene by Doping Beyond Van Hove Singularity,Advanced Functional Materials

当前位置： X-MOL 学术 › Adv. Funct. Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Significant Increase of Electron Thermal Conductivity in Dirac Semimetal Beryllonitrene by Doping Beyond Van Hove Singularity
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2022-01-12 , DOI: 10.1002/adfm.202111556
Zhen Tong _{1,

2} , Alessandro Pecchia ₃ , ChiYung Yam _{1,

2} , Hua Bao ₄ , Traian Dumitrică ₅ , Thomas Frauenheim _{1,

2,

6}

Affiliation

2D beryllium polynitrides or beryllonitrene is a newly synthesized layered material displaying anisotropic Dirac cones and van Hove singularity (VHS) located only ≈0.5 eV above the Fermi level. Using the Boltzmann transport equation with many-body effects and first-principles calculations, it is uncovered that beryllonitrene has an in-plane anisotropic room-temperature phonon thermal conductivity (κ_ph) of 78.6 and 98.8 W mK⁻¹, and an electron thermal conductivity (κ_e) of 23.0 and 60.7 W mK⁻¹, along the in-plane directions. κ_ph is dominated by the large heat capacity flexural acoustic (ZA) modes, which are susceptible to three-phonon and four-phonon scatterings but rather immune to scattering onto electrons. Filling the Dirac cones till VHS and above gradually enhances the phonon–electron coupling and monotonically decreases κ_ph by up to 55%. Instead, κ_e displays unusual nonmonotonic variations with the increase in the carrier density and follows the electron density of states at corresponding Fermi levels. The results shed light on the thermal and electrical transport properties in beryllonitrene and reveal a thermal conductivity modulation mechanism that includes a 60% increase of κ_e upon filling of the Dirac cones until VHS.

中文翻译：

通过超越范霍夫奇点掺杂显着提高狄拉克半金属铍氮的电子热导率

二维铍多氮化物或铍氮是一种新合成的层状材料，显示出各向异性的狄拉克锥和范霍夫奇点 (VHS)，仅高于费米能级≈ 0.5 eV。使用具有多体效应和第一性原理计算的玻尔兹曼输运方程，发现铍氮的面内各向异性室温声子热导率 ( κ _ph ) 分别为 78.6 和 98.8 W mK ^-1，电子热沿面内方向的电导率 ( κ _e ) 为 23.0 和 60.7 W mK ^{-1 。}κph _{_}主要由大热容量弯曲声 (ZA) 模式主导，该模式易受三声子和四声子散射的影响，但对电子散射免疫。填充狄拉克锥直到 VHS 及以上逐渐增强声子 - 电子耦合并单调降低κ _ph达 55%。相反，随着载流子密度的增加， κ _e表现出不寻常的非单调变化，并遵循相应费米能级的电子态密度。结果揭示了铍氮的热和电传输特性，并揭示了一种热导调节机制，包括在填充狄拉克锥直到 VHS 时κ _{e增加 60%。}

更新日期：2022-01-12

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11