• Hugenschmidt, Christoph
• Chioncel, Liviu
• Ketels, Josef
• Sekania, Mikheil
• Unglert, Nico
• Bonart, Jakob
• James, Alyn D. N.
• Böni, Peter
• Leitner, Michael

Abstract

<jats:sec><jats:label /><jats:p>2D angular correlation of the positron annihilation radiation (2D‐ACAR) spectra are measured foralong high‐symmetry directions and compared with first‐principles calculations based on density functional theory (DFT). This allows the modeling of the Fermi surface in terms of ellipsoid electron pockets centered at <jats:italic>X</jats:italic>‐points elongated along the <jats:italic>Σ</jats:italic> axis (<jats:italic>Γ</jats:italic> direction). The obtained structure is in agreement with quantum oscillation measurements and previous band structure calculations. For the isostructural topologically nontrivial , the similar ellipsoids are connected through necks that have significantly smaller radii in the case of . A theoretical analysis of the 2D‐ACAR spectra is also conducted forincluding the on‐site repulsion <jats:italic>U</jats:italic>‐correction to the local density approximation (LDA+<jats:italic>U</jats:italic>) of the DFT. The similarities of the 2D‐ACAR spectra and the Fermi surface projections of these two compounds allow to infer that bothandare topologically trivial correlated metals.</jats:p></jats:sec>

Topics

• density
• impedance spectroscopy
• surface
• compound
• theory
• positron annihilation lifetime spectroscopy
• density functional theory
• size-exclusion chromatography
• band structure