2017/11/30 by S. V. Ramankutty, Shyama Varier Ramankutty, J. Henke +30
Materials Science · Physics and Astronomy · #2D Materials and Applications #Angle-resolved photoemission spectroscopy #Dirac (video compression format) #Dirac fermion #Electronic band structure #Electronic structure #Fermi surface #Geometric phase #Rare-earth and actinide compounds #Semimetal #Topological Materials and Phenomena #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.21468/scipostphys.4.2.010
published as SciPost Phys. 4, 010 (2018) · 26 pages, 10 figures, revised submission to SciPost after including changes requested by referees. All referee reports are open and can be viewed here: https://scipost.org/submissions/1711.07165v2/
openalex created_date 2017/12/04 · arxiv created 2018/01/21 · openalex publication_date 2018/02/21 · arxiv updated 2018/02/22 · openalex updated_date 2026/08/05
SrMnSb 2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mn>2</mml:mn> </mml:msub> </mml:math> is suggested to be a magnetic topological semimetal. It contains square, 2D Sb planes with non-symmorphic crystal symmetries that could protect band crossings, offering the possibility of a quasi-2D, robust Dirac semi-metal in the form of a stable, bulk (3D) crystal. Here, we report a combined and comprehensive experimental and theoretical investigation of the electronic structure of SrMnSb 2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mn>2</mml:mn> </mml:msub> </mml:math> , including the first ARPES data on this compound. SrMnSb 2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mn>2</mml:mn> </mml:msub> </mml:math> possesses a small Fermi surface originating from highly 2D, sharp and linearly dispersing bands (the ‘Y-states’) around the (0,/a)-point in k <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>k</mml:mi> </mml:math> -space. The ARPES Fermi surface agrees perfectly with that from bulk-sensitive Shubnikov de Haas data from the same crystals, proving the Y-states to be responsible for electrical conductivity in SrMnSb 2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mn>2</mml:mn> </mml:msub> </mml:math> . DFT and tight binding (TB) methods are used to model the electronic states, and both show good agreement with the ARPES data. Despite the great promise of the latter, both theory approaches show the Y-states to be gapped above E F <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mi>F</mml:mi> </mml:msub> </mml:math> , suggesting trivial topology. Subsequent analysis within both theory approaches shows the Berry phase to be zero, indicating the non-topological character of the transport in SrMnSb 2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi/> <mml:mn>2</mml:mn> </mml:msub> </mml:math> , a conclusion backed up by the analysis of the quantum oscillation data from our crystals.