Kar Satyaki
A.K.P.C. Mahavidyalaya, Bengai, Hooghly-712611, West Bengal, India.
J Phys Condens Matter. 2021 May 7;33(22). doi: 10.1088/1361-648X/abe8a2.
Nodal line semimetals (NLSM) exhibit interesting quantum oscillation (QO) characteristics when acted upon by a strong magnetic field. We study the combined effect of strong direct and alternating magnetic field, perpendicular to the nodal plane in an untilted NLSM in order to probe the behavior of the low lying Landau level states that can periodically become gapless for suitably chosen field parameters. The oscillatory field variation, as opposed to a steady one, has interesting impact on the QO phenomena with the Landau tubes crossing the Fermi surface extremally two times per cycle. Furthermore, the low energy modes can witness Landau-Zener like transitions between valence and conduction band providing further routes to conduction. We discuss such transition phenomena following the framework of adiabatic-impulse approximation for slow quenches. Next we also investigate the effect of oscillating magnetic field acting parallel to the nodal loop where topologically nontrivial magnetic oscillations at low energies can be witnessed. Therefore, with proper parameters chosen, one can engineer topological transitions to occur periodically in such systems as the oscillating field is swept through its cycles.
节点线半金属(NLSM)在强磁场作用下表现出有趣的量子振荡(QO)特性。我们研究强直流磁场和交变磁场的联合效应,该磁场垂直于未倾斜的NLSM中的节点平面,以便探究低能朗道能级态的行为,对于适当选择的场参数,这些态可以周期性地变为无隙态。与稳定磁场相反,振荡磁场变化对QO现象有有趣的影响,朗道管每周期与费米面极端交叉两次。此外,低能模式可以见证价带和导带之间类似朗道 - 齐纳的跃迁,从而提供进一步的导电途径。我们按照慢猝灭的绝热 - 脉冲近似框架讨论这种跃迁现象。接下来,我们还研究平行于节点环作用的振荡磁场的影响,在这种情况下可以见证低能下的拓扑非平凡磁振荡。因此,通过选择适当的参数,当振荡磁场扫过其周期时,人们可以设计在这样的系统中周期性地发生拓扑转变。