Origin of competing charge density waves in kagome metal ScV$_6$Sn$_6$
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| Format: | Preprint |
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2024
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| _version_ | 1866912142169473024 |
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| author | Wang, Kang Chen, Siyu Kim, Sun-Woo Monserrat, Bartomeu |
| author_facet | Wang, Kang Chen, Siyu Kim, Sun-Woo Monserrat, Bartomeu |
| contents | Understanding competing charge density wave (CDW) orders in the bilayer kagome metal ScV$_6$Sn$_6$ remains challenging. Experimentally, upon cooling, short-range order with wave vector $\mathbf{q}_{2}=(\frac{1}{3},\frac{1}{3},\frac{1}{2})$ forms, which is subsequently suppressed by the condensation of long-range $\mathbf{q}_{3}=(\frac{1}{3},\frac{1}{3},\frac{1}{3})$ CDW order at lower temperature. Theoretically, however, the $\mathbf{q}_{2}$ CDW is predicted as the ground state, leaving the CDW mechanism elusive. Here, using anharmonic phonon-phonon calculations combined with density functional theory, we predict a temperature-driven structural phase transitions from the high-temperature pristine phase to the $\mathbf{q}_{2}$ CDW, followed by the low-temperature $\mathbf{q}_{3}$ CDW, explaining experimental observations. We demonstrate that semi-core electron states stabilize the $\mathbf{q}_{3}$ CDW over the $\mathbf{q}_{2}$ CDW. Furthermore, we find that the out-of-plane lattice parameter controls the competing CDWs, motivating us to propose compressive bi-axial strain as an experimental protocol to stabilize the $\mathbf{q}_{2}$ CDW. Finally, we suggest Ge or Pb doping at the Sn site as another potential avenue to control CDW instabilities. Our work provides a full theory of CDWs in ScV$_6$Sn$_6$, rationalizing experimental observations and resolving earlier discrepancies between theory and experiment. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_17058 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Origin of competing charge density waves in kagome metal ScV$_6$Sn$_6$ Wang, Kang Chen, Siyu Kim, Sun-Woo Monserrat, Bartomeu Strongly Correlated Electrons Materials Science Understanding competing charge density wave (CDW) orders in the bilayer kagome metal ScV$_6$Sn$_6$ remains challenging. Experimentally, upon cooling, short-range order with wave vector $\mathbf{q}_{2}=(\frac{1}{3},\frac{1}{3},\frac{1}{2})$ forms, which is subsequently suppressed by the condensation of long-range $\mathbf{q}_{3}=(\frac{1}{3},\frac{1}{3},\frac{1}{3})$ CDW order at lower temperature. Theoretically, however, the $\mathbf{q}_{2}$ CDW is predicted as the ground state, leaving the CDW mechanism elusive. Here, using anharmonic phonon-phonon calculations combined with density functional theory, we predict a temperature-driven structural phase transitions from the high-temperature pristine phase to the $\mathbf{q}_{2}$ CDW, followed by the low-temperature $\mathbf{q}_{3}$ CDW, explaining experimental observations. We demonstrate that semi-core electron states stabilize the $\mathbf{q}_{3}$ CDW over the $\mathbf{q}_{2}$ CDW. Furthermore, we find that the out-of-plane lattice parameter controls the competing CDWs, motivating us to propose compressive bi-axial strain as an experimental protocol to stabilize the $\mathbf{q}_{2}$ CDW. Finally, we suggest Ge or Pb doping at the Sn site as another potential avenue to control CDW instabilities. Our work provides a full theory of CDWs in ScV$_6$Sn$_6$, rationalizing experimental observations and resolving earlier discrepancies between theory and experiment. |
| title | Origin of competing charge density waves in kagome metal ScV$_6$Sn$_6$ |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2403.17058 |