Li Ding, Hu Yanxiao, Ding Guangqian, Feng Chunbao, Li Dengfeng
School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, People's Republic of China.
Institute for Advanced Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065, People's Republic of China.
Nanotechnology. 2022 Mar 17;33(23). doi: 10.1088/1361-6528/ac58a6.
Two-dimensional transition metals borides TiBhave excellent magnetic and electronic properties and great potential in metal-ion batteries and energy storage. The thermal management is important for the safety and stability in these applications. We investigated the lattice dynamical and thermal transport properties of bulk-TiBand its two-dimensional (2D) counterparts based on density functional theory combined with solving phonon Boltzmann transport equation. The Poisson's ratio of bulk-TiBis positive while it changes to negative for monolayer TiB. We found that dimension reduction can cause the room-temperature in-plane lattice thermal conductivity decrease, which is opposite the trend of MoS, MoSe, WSeand SnSe. Additionally, the room temperature thermal conductivity of mono-TiBis only one sixth of that for bulk-TiB. It is attributed to the higher Debye temperature and stronger bonding stiffness in bulk-TiB. The bulk-TiBhas higher phonon group velocity and weaker anharmonic effect comparing with its 2D counterparts. On the other hand, the room temperature lattice thermal conductivity of mono-TiBis two times higher than that of mono-TiB, which is due to three-phonon selection rule caused by the horizontal mirror symmetry.
二维过渡金属硼化物TiB具有优异的磁性和电子特性，在金属离子电池和能量存储方面具有巨大潜力。热管理对于这些应用中的安全性和稳定性至关重要。我们基于密度泛函理论并结合求解声子玻尔兹曼输运方程，研究了块状TiB及其二维对应物的晶格动力学和热输运特性。块状TiB的泊松比为正，而单层TiB的泊松比变为负。我们发现尺寸减小会导致室温面内晶格热导率降低，这与MoS、MoSe、WSe和SnSe的趋势相反。此外，单层TiB的室温热导率仅为块状TiB的六分之一。这归因于块状TiB中较高的德拜温度和较强的键合刚度。与二维对应物相比，块状TiB具有更高的声子群速度和较弱的非谐效应。另一方面，单层TiB的室温晶格热导率比单层TiB高两倍，这是由于水平镜像对称引起的三声子选择规则。
