Heikes Colin, Liu I-Lin, Metz Tristin, Eckberg Chris, Neves Paul, Wu Yan, Hung Linda, Piccoli Phil, Cao Huibo, Leao Juscelino, Paglione Johnpierre, Yildirim Taner, Butch Nicholas P, Ratcliff William
NIST Center for Neutron Research, NIST, Gaithersburg, Maryland 20899, USA.
Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA.
Phys Rev Mater. 2018 Jul;2(7). doi: 10.1103/physrevmaterials.2.074202.
The noncentrosymmetric Weyl semimetal candidate MoTe was investigated through neutron-diffraction and transport measurements at pressures up to 1.5 GPa and at temperatures down to 40 mK. Centrosymmetric and noncentrosymmetric structural phases were found to coexist in the superconducting state. Density functional theory (DFT) calculations reveal that the strength of the electron-phonon coupling is similar for both crystal structures. Furthermore, it was found that by controlling nonhydrostatic components of stress, it is possible to mechanically control the ground-state crystal structure. This allows for the tuning of crystal symmetry in the superconducting phase from centrosymmetric to noncentrosymmetric. DFT calculations support this strain control of crystal structure. This mechanical control of crystal symmetry gives a route to tuning the band topology of MoTe and possibly the topology of the superconducting state.
通过在高达1.5吉帕的压力和低至40毫开尔文的温度下进行中子衍射和输运测量，对非中心对称的外尔半金属候选材料碲化钼（MoTe）展开了研究。结果发现，中心对称和非中心对称结构相在超导态中共存。密度泛函理论（DFT）计算表明，两种晶体结构的电子 - 声子耦合强度相似。此外，研究发现，通过控制应力的非静水分量，可以机械地控制基态晶体结构。这使得在超导相中能够将晶体对称性从中心对称调整为非中心对称。DFT计算支持这种对晶体结构的应变控制。这种对晶体对称性的机械控制为调整碲化钼的能带拓扑结构以及可能的超导态拓扑结构提供了一条途径。
