WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Lithiated Single-Layer Holey Mo8s12: Electronic, Magnetic and Vibrational Characteristics(Elsevier, 2025) Şahin, Hasan; Cetin, Z.; Yagmurcukardes, M.; Sahin, H.; 04.04. Department of Photonics; 04. Faculty of Science; 01. Izmir Institute of TechnologyMotivated by the recent experimental realization of holey transition metal chalcogenides[ACS Applied Materials & Interfaces 2022, 14(23), 27056-27062], in this study, the holey structure of Mo8S12 is investigated by means of density functional theory-based calculations. The geometry optimization and phonon band dispersion calculations show the structural and dynamical stability of free-standing holey single-layer Mo8S12. In addition, electronic band dispersions reveal the direct band gap semiconducting nature of the structure. In order to investigate the lithiation capacity of single-layer Mo8S12, effect of Li doping on the properties of Mo8S12 is analyzed by considering both one- and double-sided lithiation. Our calculations indicate that single Li atom is chemically adsorbed on top of Mo8S12 through the Mo-Mo bridge site and experiences relatively high diffusion barrier at room temperature, which shows the chemical stability of adsorbed Lion the surface. As one surface of single-layer Mo8S12 is fully saturated with Li atoms, a dynamically stable semiconducting structure is formed. Moreover, the double-side lithiated structure is found to be dynamically stable derivative of Mo8S12. The corresponding electronic band structures reveals the semiconducting behavior of the double-side lithiated single-layer. The predicted voltage of lithiated Mo8S12 reveal its potential for battery applications as a cathode material. Apparently, either one or two side lithiation allows one to significantly tune the electronic and magnetic properties of Mo8S12. Overall, tunable electronic band gap of single-layer holey Mo8S12 via lithiation could make it suitable candidate for optoelectronic devices.Article Citation - WoS: 4Citation - Scopus: 4Ultra-Thin Double-Layered Hexagonal Cui: Strain Tunable Properties and Robust Semiconducting Behavior(Iop Publishing Ltd, 2024) Şahin, Hasan; Yağmurcukardeş, Mehmet; Yagmurcukardes, M.; 04.04. Department of Photonics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, the freestanding form of ultra-thin CuI crystals, which have recently been synthesized experimentally, and their strain-dependent properties are investigated by means of density functional theory calculations. Structural optimizations show that CuI crystallizes in a double-layered hexagonal crystal (DLHC) structure. While phonon calculations predict that DLHC CuI crystals are dynamically stable, subsequent vibrational spectrum analyzes reveal that this structure has four unique Raman-active modes, allowing it to be easily distinguished from similar ultra-thin two-dimensional materials. Electronically, DLHC CuI is found to be a semiconductor with a direct band gap of 3.24 eV which is larger than that of its wurtzite and zincblende phases. Furthermore, it is found that in both armchair (AC) and zigzag (ZZ) orientations the elastic instabilities occur over the high strain strengths indicating the soft nature of CuI layer. In addition, the stress-strain curve along the AC direction reveal that DLHC CuI undergoes a structural phase transition between the 4% and 5% tensile uniaxial strains as indicated by a sudden drop of the stress in the lattice. Moreover, the phonon band dispersions show that the phononic instability occurs at much smaller strain along the ZZ direction than that of along the AC direction. Furthermore, the external strain direction can be deduced from the predicted Raman spectra through the splitting rates of the doubly degenerate in-plane vibrations. The mobility of the hole carriers display highly anisotropic characteristic as the applied strain reaches 5% along the AC direction. Due to its anomalous strain-dependent electronic features and elastically soft nature, DLHC of CuI is a potential candidate for future electro-mechanical applications.