物理学报2024，Vol.73Issue(14)：177-184,8.DOI:10.7498/aps.73.20240557
结构相变引起单层RuSe2载流子迁移率的提高
Structural phase transition induced enhancement of carrier mobility of monolayer RuSe2
摘要
Abstract
Transition metal dichalcogenides(TMDs)is an important member of two-dimensional material family,which has various crystal structures and physical properties,thus providing a broad platform for scientific research and device applications.The diversity of TMD's properties arises not only from their relatively large family but also from the variety of their crystal structure phases.The most common structure of TMD is the trigonal prismatic phase(H phase)and the octahedral phase(T phase).Studies have shown that,in addition to these two high-symmetry phases,TMD has other distorted phases.Distorted phase often exhibits different physical properties from symmetric phases and can perform better in certain systems.Because the structural differences between different distorted phases are sometimes very small,it is experimentally challenging to observe multiple distorted phases coexisting.Therefore,it is meaningful to theoretically investigate the structural stability and physical properties of different distorted phases.In this study,we investigate the structure and phase transition of monolayer RuSe2 through first-principles calculation.While confirming that its ground state is a the dimerized phase(T′phase),we find the presence of another energetically competitive trimerized phase(T(''')phase).By comparing the energy values of four different structures and combining the results of phonon spectra and molecular dynamics simulations,we predict the stability of the T(''')phase at room temperature.Because the H phase and T phase of two-dimensional RuSe2 have already been observed experimentally,and considering the fact that T(''')phase has much lower energy than the H and T phases,it is highly likely that the T(''')phase exists in experiment.Combining the calculations of the phase transition barrier and the molecular dynamics simulations,we anticipate that applying a slight stress to the T′phase structure at room temperature can induce a lattice transition from T′phase to T(''')phase,resulting in significant changes in the band structure and carrier mobility,with the bandgap changing from an indirect bandgap of 1.11 eV to a direct bandgap of 0.71 eV,and the carrier mobility in the armchair direction increasing from 0.82× 103 cm2·V-1·s-1 to 3.22 × 103 cm2·V-1·s-1,an approximately threefold enhancement.In this work,two possible coexisting distorted phases in monolayer RuSe2 are compared with each other and studied,and their electronic structures and carrier mobilities are analyzed,thereby facilitating experimental research on two-dimensional RuSe2 materials and their applications in future electronic devices.关键词
二硒化钌/结构相变/载流子迁移率/第一性原理计算Key words
RuSe2/phase transition/carrier mobility/first-principles calculation引用本文复制引用
陆康俊,王一帆,夏谦,张贵涛,陈乾..结构相变引起单层RuSe2载流子迁移率的提高[J].物理学报,2024,73(14):177-184,8.基金项目
国家重点研发计划(批准号:2022YFA1503103)、国家自然科学基金(批准号:22033002)和江苏省研究生科研创新计划(批准号:KYCX23_0223)资助的课题. Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1503103),the National Natural Science Foundation of China(Grant No.22033002),and the Postgraduate Research & Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX23_0223). （批准号:2022YFA1503103）
