https://scholar.dgist.ac.kr/handle/20.500.11750/31 2026-08-03T11:36:41Z https://scholar.dgist.ac.kr/handle/20.500.11750/60590 Title: A comparative synthesis study of α-MnTe across solid-state, Arc-melting, and Te-flux routes Author(s): Kim, Bomin; Jeong, Yunseong; Baek, Wonjung; Kim, Hobyeong; Rhee, Taeseong; Cho, Beopgil; Choi, Woo-Jae; Ha, Jae-Hyun; Park, Jaemun; Hong, Jung-Il; Kwon, Yong Seung; Seo, Jungpil; Park, Keeseong Abstract: Although alpha-MnTe has attracted renewed interest in both thermoelectric and altermagnetic contexts, direct comparisons of practically accessible synthesis routes within a common experimental framework remain limited. Here, we compare conventional solid-state reaction, arc melting and Te self-flux growth methods under a common framework of composition control and thermal history. Within the explored conditions, the phase outcome depends not only on the nominal starting composition but also on route-dependent synthesis environments, including volatilization in sealed ampoules, repeated remelting and rapid quenching in arc melting, and crystal-flux interfacial segregation in Te self-flux growth. In the solid-state route, slow heating with a slightly Mn-rich starting composition was associated with reduced MnTe2 and alpha-MnTe-dominant products. Arc melting yielded alpha-MnTe-dominant products without post-annealing, accompanied by dendritic-like microstructures. Te self-flux growth yielded single crystals, although a minor MnTe2-rich interfacial or surface layer often remained. While the present dataset does not define a rigorous phase boundary or a definitive mechanistic model, it provides a systematic comparative framework for route-dependent phase outcomes and impurity persistence in alpha-MnTe synthesis. 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60502 Title: A comparative synthesis study of α-MnTe across solid-state, Arc-melting, and Te-flux routes Author(s): Kim, Bomin; Jeong, Yunseong; Baek, Wonjung; Kim, Hobyeong; Rhee, Taeseong; Cho, Beopgil; Choi, Woo-Jae; Ha, Jae-Hyun; Park, Jaemun; Hong, Jung-Il; Kwon, Yong Seung; Seo, Jungpil; Park, Keeseong Abstract: Although alpha-MnTe has attracted renewed interest in both thermoelectric and altermagnetic contexts, direct comparisons of practically accessible synthesis routes within a common experimental framework remain limited. Here, we compare conventional solid-state reaction, arc melting and Te self-flux growth methods under a common framework of composition control and thermal history. Within the explored conditions, the phase outcome depends not only on the nominal starting composition but also on route-dependent synthesis environments, including volatilization in sealed ampoules, repeated remelting and rapid quenching in arc melting, and crystal-flux interfacial segregation in Te self-flux growth. In the solid-state route, slow heating with a slightly Mn-rich starting composition was associated with reduced MnTe2 and alpha-MnTe-dominant products. Arc melting yielded alpha-MnTe-dominant products without post-annealing, accompanied by dendritic-like microstructures. Te self-flux growth yielded single crystals, although a minor MnTe2-rich interfacial or surface layer often remained. While the present dataset does not define a rigorous phase boundary or a definitive mechanistic model, it provides a systematic comparative framework for route-dependent phase outcomes and impurity persistence in alpha-MnTe synthesis. 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59272 Title: Polaronic Quasiparticles in the Valence-Transition Compound TmSe_{1-x}Te_{x} Author(s): Min, Chul-Hee; Müller, Simon; Choi, Woojae; Dudy, Lenart; Zabolotnyy, Volodymyr B.; Heber, Michael; Denlinger, Jonathan D.; Kang, Chang-jong; Kalläne, Matthias; Wind, Nils O.; Scholz, Markus R.; Lee, Tienlin; Schlueter, Christoph; Gloskovskii, Andrei V.; Rienks, Emile D.L.; Hinkov, Vladimir; Bentmann, Hendrik; Kwon, Yong Seung; Reinert, Friedrich T.; Kim, H. D.; Rossnagel, Kai Abstract: Exotic quasiparticle states have been proposed in mixed-valent compounds exhibiting valence transitions. However, clear spectroscopic evidence identifying these states has remained elusive. Using synchrotron-based hard x-ray and extreme ultraviolet photoemission spectroscopy, we have probed the Tm 3d and 4f emissions in TmSe_{1-x}Te_{x}, where a Te concentration-dependent semimetal-insulator transition occurs alongside the valence transition. Our photoemission results, which are characteristic of the bulk, track this combined transition across the critical concentration (x_{c}=0.29). Notably, our results reveal a noninteger valence for the insulating phase and a novel quasiparticle excitation in the semimetallic phase: a Holstein polaron that extends beyond the standard periodic Anderson model. 2025-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58383 Title: Glassy relaxation and weak vortex pinning in anisotropic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 single crystals Author(s): Haberkorn, Néstor; Kwon, Yong Seung Abstract: We present a comprehensive study on the vortex dynamics of (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 ​ single crystals, characterized by magnetization measurements. With a superconducting critical temperature of 32 K, this material is notable for its substantial anisotropy (5–6), which significantly influences the intrinsic vortex fluctuations. Our results reveal low critical current densities, i. e. Jc∼0.6 MA/cm2 at 1.8 K and low magnetic fields. The magnetic field dependences of Jc exhibit a fishtail or second peak in the magnetization, a feature commonly associated with weak vortex pinning and vortex relaxation crossovers. Moreover, the flux creep rates are exceptionally large at low fields and temperatures. Through Maley's analysis, we extract low vortex pinning energies (∼50 K) and glassy exponents that are consistent with expectations for single-vortex pinning, progressively evolving towards vortex bundles. These findings enhance our understanding of vortex dynamics in iron-based superconductors, highlighting the key role of intrinsic vortex fluctuations in the vortex phase diagram. © 2025 Elsevier B.V. 2025-05-31T15:00:00Z