The surface state of URu2Si2

Formation of the Coherent Heavy Fermion Liquid at the Hidden Order Transition inURu2Si2

“…We do not observe any appreciable dispersion along k z for features 2, 3, and 4, while feature 1 has already been ascribed to a surface-derived origin [14] and feature 5 is apparent at only very few photon energies. The main effect of varying photon energies observed here is to strongly modulate the photoelectron matrix elements of these different features, suggesting that these states have substantially different orbital character.…”

“…1 f. Feature 1 has been previously shown to be of surface origin and does not show significant changes across T HO , while feature 2 corresponds to a light hole-like band which has been attributed to a bulk state [13,14]. Feature 3 exhibits an 'M'-shaped dispersion and was also reported for hν = 7 eV [15,16].…”

“…One of the most prominent example is the enigmatic 'hidden order' (HO) state in URu 2 Si 2 , which is characterized by a large loss of entropy at T HO =17.5 K [1,2]. Although a multitude of theoretical scenarios have been proposed to explain the HO transition [3][4][5][6][7][8][9], our lack of knowledge of the complex and still debated electronic structure of URu 2 Si 2 [10][11][12][13][14][15][16] remains the major obstacle to developing a definitive understanding of this phase. Here we disentangle the low-energy electronic structure of URu 2 Si 2 by means of angle-resolved photoemission spectroscopy (ARPES) as a function of both excitation photon energy and temperature.…”

Translational Symmetry Breaking and Gapping of Heavy-Quasiparticle Pocket in URu2Si2

“…1(f) show the existence of a hole pocket. While the hole-like band observed at two different photon energies was experimentally shown as a surface-originated state2227, the hole pocket is also suggested as a surface-derived state owing to the absence of k z dependence and its inconsistency with bulk-sensitive measurements (see Supplementary Fig. S2 and Supplementary Discussion 1 for details).…”

Photoemission investigations of URu2Si2

“…The discussion of this interesting possibility, later continued in [36] was further neglected, since this particular feature does not appear to be directly related to HO. However, because of its intensity, it is masking the fine details at E f , which makes photoemission measurements in this system most difficult.…”