Orbital- and k z -Selective Hybridization of Se 4 p and Ti 3 d States in the Charge Density Wave Phase of TiSe 2

摘要: We revisit the enduring problem of $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}2$ charge density wave (CDW) order in ${\mathrm{TiSe}}_{2}$, utilizing photon energy-dependent angle-resolved photoemission spectroscopy to probe full three-dimensional high- and low-temperature electronic structure. Our measurements demonstrate how a mismatch dimensionality between 3D conduction bands quasi-2D valence this system leads hybridization that is strongly ${k}_{z}$ dependent. While such momentum-selective coupling can provide energy gain required form CDW, we show additional ``passenger'' states remain, which couple only weakly CDW thus dominate low-energy physics ordered phase ${\mathrm{TiSe}}_{2}$.