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Electronic structure of the candidate 2D Dirac semimetal SrMnSb2: a combined experimental and theoretical study

by S. V. Ramankutty, J. Henke, A. Schiphorst, R. Nutakki, S. Bron, G. Araizi-Kanoutas, S. K. Mishra, Lei Li, Y. K. Huang, T. K. Kim, M. Hoesch, C. Schlueter, T. -L. Lee, A. de Visser, Zhicheng Zhong, Jasper van Wezel, E. van Heumen, M. S. Golden

Submission summary

As Contributors: Shyama Varier Ramankutty · Jasper van Wezel
Arxiv Link: http://arxiv.org/abs/1711.07165v3
Date accepted: 2018-02-07
Date submitted: 2018-01-24
Submitted by: Ramankutty, Shyama Varier
Submitted to: SciPost Physics
Domain(s): Exp. & Theor.
Subject area: Condensed Matter Physics - Experiment

Abstract

SrMnSb$_2$ 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$_2$, including the first ARPES data on this compound. SrMnSb$_2$ possesses a small Fermi surface originating from highly 2D, sharp and linearly dispersing bands (the Y-states) around the (0,$\pi$/a)-point in $k$-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$_2$. 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$_F$, 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$_2$, a conclusion backed up by the analysis of the quantum oscillation data from our crystals.

Current status:

Ontology / Topics

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Angle-resolved photoemission spectroscopy (ARPES) Berry phase Dirac semimetals Shubnikov-de Haas effect SrMnSb2 Topological semimetals Transport

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