A5078779343- Topological Materials and Phenomena
- Graphene research and applications
- 2D Materials and Applications
- Surface and Thin Film Phenomena
- MXene and MAX Phase Materials
- Quantum and electron transport phenomena
- Advanced Chemical Physics Studies
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Chalcogenide Semiconductor Thin Films
- Electron and X-Ray Spectroscopy Techniques
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Iron-based superconductors research
- Magnetic and transport properties of perovskites and related materials
- nanoparticles nucleation surface interactions
- Inorganic Chemistry and Materials
- ZnO doping and properties
- Surface Chemistry and Catalysis
- Boron and Carbon Nanomaterials Research
National Sun Yat-sen University
2016-2025
National Center for Theoretical Sciences
2020-2025
National Tsing Hua University
2020-2025
National Center for Theoretical Sciences, Physics Division
2020-2025
Computational Physics (United States)
2025
Center for Theoretical Physics
2025
Korea University
2024
Institute of Physics, Academia Sinica
2021
University of California, Los Angeles
2012-2013
Iowa State University
2004-2008
The zigzag-edged triangular graphene molecules (ZTGMs) have been predicted to host ferromagnetically coupled edge states with the net spin scaling molecular size, which affords large tunability crucial for next-generation spintronics. However, scalable synthesis of ZTGMs and direct observation their long-standing challenges because molecules' high chemical instability. Here, we report bottom-up π-extended [5]triangulene atomic precision via surface-assisted cyclodehydrogenation a rationally...
We use first-principles electronic structure calculations to predict a new class of two-dimensional (2D) topological insulators (TIs) in binary compositions group III elements (B, Al, Ga, In, and Tl) bismuth (Bi) buckled honeycomb structure. identify band inversions pristine GaBi, InBi, TlBi bilayers, with gaps as large 560 meV, making these materials suitable for room-temperature applications. Furthermore, we demonstrate the possibility strain engineering that phase transition BBi AlBi...
Abstract Platinum-based transition metal dichalcogenides have been gaining renewed interest because of the development a new method to synthesize thin film structures. Here, using first-principles calculation, we explore electronic properties PtX 2 (X = S, Se, and Te) with respect thickness. For bulk layered structures (1 10 layers), octahedral 1T is most stable. Surprisingly, also find that 3R structure has comparable stability relative 1T, implying possible synthesis 3R. structure, PtS...
We discuss two-dimensional (2D) topological insulators (TIs) based on planar Bi/Sb honeycombs a SiC(0001) substrate using first-principles computations. The are shown to support nontrivial band gap as large 0.56 eV, which harbors Dirac cone lying within the gap. Effects of hydrogen atoms placed either just one side or both sides examined. hydrogenated found exhibit topologically protected edge states for zigzag well armchair edges, with wide 1.03 and 0.41 eV in bismuth antimony films,...
A large gap two-dimensional (2D) topological insulator (TI), also known as a quantum spin Hall (QSH) insulator, is highly desirable for low-power-consuming electronic devices owing to its spin-polarized backscattering-free edge conducting channels. Although many freestanding films have been predicted harbor the QSH phase, band topology of film can be modified substantially when it placed or grown on substrate, making materials realization 2D TI challenging. Here we report first-principles...
Electronic structures and band topology of a single Sb(111) bilayer in the buckled honeycomb configuration are investigated using first-principles calculations. A nontrivial topological insulating phase can be induced by tensile strain, indicating possibility realizing quantum spin Hall state for Sb thin films on suitable substrates. The presence buckling provides an advantage controlling gap through out-of-plane external electric field, making transition with six spin-polarized Dirac cones...
The formation of PtSe2 -layered films is reported in a large area by the direct plasma-assisted selenization Pt at low temperature, where temperatures, as 100 °C applied plasma power 400 W can be achieved. As thickness film exceeds 5 nm, (five monolayers) exhibits metallic behavior. A clear p-type semiconducting behavior (≈trilayers) observed with average field effective mobility 0.7 cm2 V-1 s-1 from back-gated transistor measurements reaches below 2.5 nm. full effect demonstrated thinner ,...
Spinel oxides (AB2O4) with unique crystal structures have been widely explored as promising alternative catalysts for efficient oxygen evolution reactions; however, developing novel methods to fabricate robust, cost-effective, and high-performance spinel oxide based electrocatalysts is still a great challenge. Here, utilizing complementary experimental theoretical approach, pentavalent vanadium doping in the (i.e., Co3O4 NiFe2O4) has thoroughly investigated engineer their surface enhanced...
Ligand-induced surface restructuring with heteroatomic doping is used to precisely modify the of a prototypical [Au25 (SR1 )18 ]- cluster (1) while maintaining its icosahedral Au13 core for synthesis new bimetallic [Au19 Cd3 (SR2 (2). Single-crystal X-ray diffraction studies reveal that six bidentate Au2 )3 motifs (L2) attached 1 were replaced by three quadridentate Cd(SR2 )6 (L4) create 2. Experimental and theoretical results demonstrate stronger electronic interaction between (Au2 ) core,...
The presence of two-dimensional (2D) layer-stacking heterostructures that can efficiently tune the interface properties by stacking desirable materials provides a platform to investigate some physical phenomena, such as proximity effect and magnetic exchange coupling. Here, we report observation antisymmetric magnetoresistance in van der Waals (vdW) antiferromagnetic/ferromagnetic (AFM/FM) heterostructure MnPS3/Fe3GeTe2 when temperature is below Neel MnPS3. Distinguished from two resistance...
Magnetic semimetals have increasingly emerged as lucrative platforms hosting spin-based topological phenomena in real and momentum spaces. Cr1+δ Te2 is a self-intercalated magnetic transition metal dichalcogenide (TMD), which exhibits magnetism tunable electron filling. While recent studies explored real-space Berry curvature effects, similar considerations of momentum-space are lacking. Here, the electronic structure transport properties epitaxial thin films systematically investigated over...
We performed global structural optimizations for neutral aluminum clusters ${\mathrm{Al}}_{n}$ ($n$ up to 23) using a genetic algorithm (GA) coupled with tight-binding interatomic potential. Structural candidates obtained from our GA search were further optimized by first-principles total energy calculations. report the lowest structures of $(n=2\ensuremath{-}23)$. found that icosahedral structure ${\mathrm{Al}}_{13}$ serves as core growth ${\mathrm{Al}}_{14}$ ${\mathrm{Al}}_{18}$.
Electronic structures, minimum energy configurations, and band topology of strained Bi(111) single bilayers placed on a variety semiconducting insulating substrates are investigated using first-principles calculations. A topological phase diagram free-standing Bi bilayer is presented to help guide the selection suitable substrates. The hexagonal-BN identified as best candidate substrate material for supporting nontrivial thin films. planar hexagonal layer predicted under tensile strain,...
Silicene, analogous to graphene, is a one-atom-thick two-dimensional crystal of silicon which expected share many the remarkable properties graphene. The buckled honeycomb structure silicene, along with its enhanced spin-orbit coupling, endows silicene considerable advantages over graphene in that spin-split states are tunable external fields. Although low-energy Dirac cone lie at heart all novel quantum phenomena pristine sheet question whether or not these key can survive when grown...
Integration of strain engineering two-dimensional (2D) materials in order to enhance device performance is still a challenge. Here, we successfully demonstrated the thermally strained band gap transition-metal dichalcogenide bilayers by different thermal expansion coefficients between 2D and patterned sapphire structures, where MoS2 were chosen as materials. In particular, blue shift can be tunable, displaying an extraordinary capability drive electrons toward electrode under smaller driven...
Abstract Ultrathin Janus two-dimensional (2D) materials are attracting intense interest currently. Substitutional doping of 2D transition metal dichalcogenides (TMDs) is importance for tuning and possible enhancement their electronic, physical chemical properties toward industrial applications. Using systematic first-principles computations, we propose a class based on the monolayers MX 2 (M = V, Nb, Ta, Tc, or Re; X S, Se, Te) with halogen (F, Cl, Br, I) pnictogen (N, P, As, Sb, Bi)...
We have investigated topological electronic properties of freestanding bilayers group IV (C, Si, Ge, Sn, and, Pb) and V (As, Sb, Bi) elements the periodic table in buckled planar honeycomb structures under isotropic strain using first-principles calculations. Our focus is on mapping driven phase diagrams identifying transitions therein as a pathway for guiding search suitable substrates to grow two-dimensional (2D) insulators (TIs) films. Bilayers elements, excepting Pb, generally transform...
Platinum ditelluride (PtTe_{2}), a type-II Dirac semimetal, remains semimetallic in ultrathin films down to just two triatomic layers (TLs) with negative gap of -0.36 eV. Further reduction the film thickness single TL induces Lifshitz electronic transition semiconductor large positive +0.79 This is evidenced by experimental band structure mapping prepared layer-resolved molecular beam epitaxy, and comparing data first-principles calculations using hybrid functional. The results demonstrate...
Recent studies have demonstrated the feasibility of synthesizing two-dimensional (2D) Janus materials which possess intrinsic structural asymmetry. Hence, we performed a systematic first-principles study 2D transition metal dichalcogenide (TMD) monolayers based on PtXY (X,Y = S, Se, or Te). Our calculated formation energies show that these monolayer structures retain 1T phase. Furthermore, phonon spectral calculations confirm TMD are thermodynamically stable. We found PtSSe, PtSTe, and...
The search for two-dimensional (2D) materials with interesting topological properties is still attracting growing interest, as they offer exotic physical phenomena. Recently, the emergent 2D MA2Z4 has been gaining attention because it exhibits versatile due to its tunable elemental components M, A, and Z. In this study, an exhaustive coupled first-principles calculations was performed investigate 30 (M Group IV transition metals Ti, Zr, or Hf; A Si Ge; Z pnictogens N, P, As, Sb, Bi)...
Using thickness-dependent first-principles electronic structure calculations, we predict that hydrogenated ultra-thin films of tin harbor a new class two-dimensional (2D) topological insulators (TIs). A single bilayer (BL) film assumes 2D-TI phase, but it transforms into trivial insulator after hydrogenation. In contrast, with 2 and 3 BLs are found to be insulators, hydrogenation 4 BL results in non-trivial TI phase. For 1 BLs, H-passivation converts the from being metallic insulating....
Abstract We have carried out systematic first-principles electronic structure computations of growth ultrathin films compounds group III (B, Al, In, Ga and Tl) with V (N, P, As, Sb Bi) elements on Si(111) substrate, including effects hydrogenation. Two bilayers (BLs) AlBi, InBi, GaBi, TlAs TlSb are found to support a topological phase over wide range strains, in addition BBi, TlN TlBi which can be driven into the nontrivial via strain. A large band gap 134 meV is identified hydrogenated 2 BL...
We employ an on-surface assembly protocol to synthesize a single layer of two-dimensional conjugated network (Ni3(HITP)2) on Au(111) surface. The electronic coupling between the π orbital diimine ligand and d metal ion renders efficient π-conjugation. Density-functional theory calculations provide evidence non-trivial topological gap in surface-adsorbed layer. This work demonstrates that single-layer 2D metal-organic frameworks adsorbed surfaces are new class materials host quantum phases.