Tuning the electronic structure of FeTe via epitaxial strain

Recent studies in iron-chalcogenides (Fe-Chs) have attracted immense interest due to a variety of emerging properties via substituting the chalcogenide atoms between Te, Se, and S. For example, superconductivity in FeSe, topological superconductivity in FeSe0.45Te0.55, and bicollinear AFM phase in FeTe have been reported. This phase behavior is known to result from tuning the bond angle between Fe and chalcogenide atoms in such Fe-Ch compounds. By growing FeTe thin films on various substrates via molecular beam epitaxy (MBE), we tune the epitaxial strain imposed on FeTe, and thus manipulate the Fe-Te bond angle. Our transport and angle-resolved photoemission spectroscopy (ARPES) measurements show that such modulation in the FeTe structure effectively modifies the underlying electronic structure, giving rise to various emerging properties different from those of bulk FeTe. We further propose to systematically investigate FeTe thin films to reveal novel phases inaccessible in bulk iron chalcogenides and study the origin of such emergent behaviors.