We report a combined infrared and angle-resolved photoemission study of the electronic response of Sr 3 (Ir 1-x Ru x ) 2 O 7 (x=0, 0.22, 0.34). The low-temperature optical conductivities of the three compounds exhibit the characteristic feature of the effective total angular momentum J eff =1/2 antiferromagnetic Mott state. As the temperature increases across the antiferromagnetic ordering temperature T N , the indirect gap gradually closes whereas the direct gap remains open. In the optical conductivity of Sr 3 (Ir 0.66 Ru 0.34 ) 2 O 7 which shows a thermally driven insulator-metal transition at T N , a Drude-like response from itinerant carriers is registered in the paramagnetic phase. We observe in angle-resolved photoemission data of Sr 3 (Ir 0.66 Ru 0.34 ) 2 O 7 that the valence band shifts continuously toward the Fermi energy with the weakening of the antiferromagnetic order and crosses the Fermi level in the paramagnetic phase. Our findings demonstrate that the temperature-induced metalinsulator transition of the Sr 3 (Ir 1-x Ru x ) 2 O 7 system should be attributed to a magnetically driven band shift. * These two authors contributed equally. † yeongkwan@kaist.ac.kr ‡ soonjmoon@hanyang.ac.kr A discovery of the relativistic Mott state in Sr 2 IrO 4 [1,2] suggested that the Mott physics can be applicable in 5d transition metal oxides and stimulated extensive studies on the nature of their metal-insulator transitions. While the electromagnetic properties of Sr 2 IrO 4 were successfully explained in terms of an effective total angular momentum J eff =1/2 Mott state [1-5], a number of experimental and theoretical studies suggested that its ground state should instead be envisioned as a Slater insulator or as an intermediate phase between the Mott and Slater insulators [6-9]. In the Slater picture, the metal-insulator transition occurs at antiferromagnetic ordering temperature T N via a continuous opening of the band gap due to the appearance of a magnetic supercell [10]. Pyrochlore iridates R 2 Ir 2 O 7 (R=Nd, Sm, and Eu) which have attracted much attention as potential candidates for realizing correlated topological insulators/semimetals [11-13] exhibit a continuous metal-insulator transition accompanying the onset of antiferromagnetic order [14]. A recent angle-resolved photoemission spectroscopy (ARPES) experiment on Nd 2 Ir 2 O 7 [15] observed a gap opening at T N with an energy shift of quasiparticle peaks in a fashion similar to the Slater transition. The continuous metal-insulator transitions at T N in Cd 2 Os 2 O 7 andNaOsO 3 were also attributed to the Slater transition in early studies [16][17][18][19]. Recently, however, the metalinsulator transitions of the two osmates were revisited and ascribed to the Lifshitz-type transition [20][21][22][23].Density-functional-theory calculations showed that the metal-insulator transitions of Cd 2 Os 2 O 7 [20] and NaOsO 3 [21] involved a continuous shift of the bands away from the Fermi level and the resulting vanishing of the Fermi surface with decreasing the t...

Structural and magnetic properties, and the valence band structure of pure and Co-doped (up to 33%) Fe3O4(100) films were investigated. Reconstruction of the Fe3O4(100) surface is found to be blocked by Co doping. Doped Co ions in Fe3O4 are in a charge state of 2 + and substitute the Fe2+ in the B site of Fe3O4. All the films exhibit room temperature ferromagnetism. Co doping changes the coercivity and reduces saturation magnetization. The density of states near the Fermi level is reduced by Co doping due to the decrease of Fe2+ in the B site, which might responsible for the decrease in conductivity and magnetoresistance of Co-doped Fe3O4. The Verwey transition in the range of 100–120 K is observed for the pure Fe3O4 film, while no transition could be detected for Co-doped Fe3O4 films.

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Inositol polyphosphate multikinase (IPMK), a key enzyme in the inositol polyphosphate (IP) metabolism, is a pleiotropic signaling factor involved in major biological events including transcriptional control. In yeasts, IPMK and its IP products were known to promote the activity of SWI/SNF chromatin remodeling complex, which plays a critical role in gene expression by regulating chromatin accessibility. However, the direct linkage between IPMK and chromatin remodelers remains unclear, raising a question on how IPMK contributes to the transcriptional regulation in mammals. By employing unbiased screenings and in vivo/in vitro immunoprecipitations, here we demonstrated that IPMK physically associates with native mammalian SWI/SNF complexes by directly binding to SMARCB1, BRG1, and SMARCC1. Furthermore, we identified the specific domains required for the IPMK-SMARCB1 binding. Notably, using CUT&RUN and ATAC-seq assays, we discovered that IPMK co-localizes with BRG1 and regulates BRG1 localization as well as BRG1-mediated chromatin accessibility in a genome-wide manner (including promoter-TSS) in mouse embryonic stem cells. Finally, our mRNA-seq analyses revealed that IPMK and SMARCB1 regulate common gene sets, validating a functional link between IPMK and SWI/SNF complex. Together, these findings establish an importance of IPMK in promoter targeting of the SWI/SNF complex, thereby contributing to SWI/SNF-meditated chromatin accessibility and transcription.