Dynamical piezomagnetic effect in time-reversal-invariant Weyl semimetals with axionic charge density waves

Jiabin Yu, Benjamin J. Wieder, Chao Xing Liu

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Abstract

Charge density waves (CDWs) in Weyl semimetals (WSMs) have been shown to induce an exotic axionic insulating phase in which the sliding mode (phason) of the CDW acts as a dynamical axion field, giving rise to a large positive magnetoconductance [Wang, Phys. Rev. B 87, 161107(R) (2013)PRBMDO1098-012110.1103/PhysRevB.87.161107; Roy, Phys. Rev. B 92, 125141 (2015)PRBMDO1098-012110.1103/PhysRevB.92.125141; J. Gooth, Nature (London) 575, 315 (2019)NATUAS0028-083610.1038/s41586-019-1630-4]. In this work, we predict that dynamical strain can induce a bulk orbital magnetization in time-reversal (TR)-invariant WSMs that are gapped by a CDW. We term this effect the "dynamical piezomagnetic effect"(DPME). Unlike in J. Gooth et al. [Nature (London) 575, 315 (2019)NATUAS0028-083610.1038/s41586-019-1630-4], the DPME introduced in this work occurs in a bulk-constant (i.e., static and spatially homogeneous in the bulk) CDW, and does not rely on fluctuations, such as a phason. By studying the low-energy effective theory and a minimal tight-binding (TB) model, we find that the DPME originates from an effective valley axion field that couples the electromagnetic gauge field with a strain-induced pseudogauge field. In particular, whereas the piezoelectric effects studied in previous works are characterized by 2D Berry curvature, the DPME represents the first example of a fundamentally 3D strain effect originating from the Chern-Simons 3-form. We further f

Original languageEnglish (US)
Article number174406
JournalPhysical Review B
Volume104
Issue number17
DOIs
StatePublished - Nov 1 2021

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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