Orbital ordering and fluctuations in a kagome superconductor CsV3Sb5

Crucial role of out-of-plane Sb-$p$ orbitals in Van Hove singularity formation and electronic correlation for superconducting Kagome metal CsV$_3$Sb$_5$

“…The recently discovered Kagome metal family AV 3 Sb 5 (A =K, Rb, Cs) has gained a lot of attention by displaying various types of ordered phases intertwined with one another, such as charge density wave (CDW) [1][2][3][4][5][6][7][8][9][10][11][12][13] and superconductivity [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . Several different CDW orders have been observed and/or suggested, including the one with broken time-reversal symmetry 2-13, [26][27][28][29][30][31][32][33] .…”

“…Several different CDW orders have been observed and/or suggested, including the one with broken time-reversal symmetry 2-13, [26][27][28][29][30][31][32][33] . Whereas some important experimental features remain controversial [9][10][11][21][22][23][24][34][35][36] , theoretical studies have been actively conducted in order to provide a plausible understanding of their microscopic origins and the interrelationships between different orders, stimulating further explorations [11][12][13][15][16][17][18][19][20][21][22][23][24][25] .…”

Charge density wave in kagome superconductor AV3Sb5

“…The sudden jump of the splitting of Knight shift in Figure 2 of ref. [3] gives concrete evidence for the first order transition. And the major splitting of this Knight shift is ascribed to the orbital shift, which confirms a charge nature of this transition.…”

“…In this recent work of ref. [3], the authors carefully investigate the CDW transition in CsV 3 Sb 5 by nuclear magnetic resonance (NMR) measurements, which provides many striking results of the CsV 3 Sb 5 CDW. The first question of any phase transition is what type of this transition is.…”

New piece of the jigsaw for orbital/bond order in a kagome superconductor

“…Thus, further experimental and theoretical investigation on the interplay of electronic and lattice degrees of freedom is necessary. Song et al [6] from the University of Science and Technology of China performed a site-selective nuclear magnetic resonance on both 51 V and 133 Cs nuclei in a highquality CsV 3 Sb 5 single crystal. A first-order phase transition with a three-dimensional (3D) structural distortion was identified.…”