Abstract
The electron-phonon interaction (EPI) is instrumental in a wide variety of phenomena in solid-state physics, such as electrical resistivity in metals, carrier mobility, optical transition, and polaron effects in semiconductors, lifetime of hot carriers, transition temperature in BCS superconductors, and even spin relaxation in diamond nitrogen-vacancy centers for quantum information processing. However, due to the weak EPI strength, most phenomena have focused on electronic properties rather than on phonon properties. One prominent exception is the Kohn anomaly, where phonon softening can emerge when the phonon wave vector nests the Fermi surface of metals. Here we report a new class of Kohn anomaly in a topological Weyl semimetal (WSM), predicted by field-theoretical calculations, and experimentally observed through inelastic X-ray and neutron scattering on WSM tantalum phosphide. Compared to the conventional Kohn anomaly, the Fermi surface in a WSM exhibits multiple topological singularities of Weyl nodes, leading to a distinct nesting condition with chiral selection, a power-law divergence, and non-negligible dynamical effects. Our work brings the concept of the Kohn anomaly into WSMs and sheds light on elucidating the EPI mechanism in emergent topological materials.
| Original language | English |
|---|---|
| Article number | 236401 |
| Journal | Physical Review Letters |
| Volume | 124 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 12 2020 |
Funding
The authors thank S. Y. Xu for the helpful discussions. T. N. thanks the support from the MIT SMA-2 Fellowship Program and MIT Sow-Hsin Chen Fellowship. N. A. acknowledges the support of the National Science Foundation Graduate Research Fellowship Program under Grant No. 1122374. R. P. P. thanks the support from Fomento Económico Mexicano (FEMSA) and ITESM. A. A. thanks the support of MIT John Reed fund. Y. T. and Z. D. thank for the support from DOD Defense Advanced Research Projects Agency (DARPA) Materials for Transduction (MATRIX) program under Grant No. HR0011-16-2-0041. D. A. T. was sponsored by the Laboratory Directed Research and Development Program (LDRD) of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy (Project No. 9533). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research on neutron scattering used neutron research facilities at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory and at the NIST Center for Neutron Research (NCNR), at the National Institute of Standards and Technology, an agency of the U.S. Department of Commerce. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. M. L. acknowledges the neutron sample alignment support from MIT Nuclear Reactor Laboratory Seed Fund Program. T. N., N. A., F. H. and M. L. acknowledge the support from the U.S. Department of Energy (DOE), Office of Science (SC), Basic Energy Sciences (BES), Award No. DE-SC0020148. The authors thank S. Y. Xu for the helpful discussions. T. N. thanks the support from the MIT SMA-2 Fellowship Program and MIT Sow-Hsin Chen Fellowship. N. A. acknowledges the support of the National Science Foundation Graduate Research Fellowship Program under Grant No. 1122374. R. P. P. thanks the support from Fomento Econ??mico Mexicano (FEMSA) and ITESM. A. A. thanks the support of MIT John Reed fund. Y. T. and Z. D. thank for the support from DOD Defense Advanced Research Projects Agency (DARPA) Materials for Transduction (MATRIX) program under Grant No. HR0011-16-2-0041. D. A. T. was sponsored by the Laboratory Directed Research and Development Program (LDRD) of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy (Project No. 9533). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research on neutron scattering used neutron research facilities at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory and at the NIST Center for Neutron Research (NCNR), at the National Institute of Standards and Technology, an agency of the U.S. Department of Commerce. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. M. L. acknowledges the neutron sample alignment support from MIT Nuclear Reactor Laboratory Seed Fund Program. T. N., N. A., F. H. and M. L. acknowledge the support from the U.S. Department of Energy (DOE), Office of Science (SC), Basic Energy Sciences (BES), Award No. DE-SC0020148.
| Funders | Funder number |
|---|---|
| FEMSA | |
| Fomento Económico Mexicano | |
| MIT John Reed fund | |
| MIT Nuclear Reactor Laboratory Seed Fund Program | |
| MIT Sow-Hsin Chen Fellowship | |
| National Science Foundation | |
| U.S. Department of Energy | 9533 |
| U.S. Department of Energy | |
| Directorate for Education and Human Resources | 1122374 |
| Directorate for Education and Human Resources | |
| National Institute of Standards and Technology | |
| Defense Advanced Research Projects Agency | HR0011-16-2-0041 |
| Defense Advanced Research Projects Agency | |
| U.S. Department of Commerce | |
| Office of Science | |
| Basic Energy Sciences | DE-SC0020148 |
| Basic Energy Sciences | |
| Argonne National Laboratory | DE-AC02-06CH11357 |
| Argonne National Laboratory | |
| Oak Ridge National Laboratory | |
| Massachusetts Institute of Technology | |
| Laboratory Directed Research and Development | |
| NIST Center for Neutron Research | |
| Instituto Tecnológico y de Estudios Superiores de Monterrey |