Wave packet dynamics in monolayer MoS2 with and without a magnetic field

Abstract

We study the dynamics of electrons in monolayer Molybdenum Disulfide (MoS2), in the absence as well as presence of a transverse magnetic field. Considering the initial electronic wave function to be a Gaussian wave packet, we calculate the time dependent expectation value of position and velocity operators. In the absence of the magnetic field, the time dependent average values of position and velocity show damped oscillations dependent on the width of the wave packet. In the presence of a transverse magnetic field, the wave packet amplitude shows oscillatory behaviour over short timescales associated with classical cyclotron orbit, followed by the phenomena of spontaneous collapse and revival over larger timescales. We relate the timescales of these effects and our results can be useful for the interpretation of experiments with trapped ions.

Zitterbewegung and Klein-tunneling phenomena for transient quantum waves

“…29, which are known to exhibit the ZBW. On the theoretical side, the ZBW is explored by means of the time-evolution in Heisenberg's picture of the expectation value of the electrons position for wave packets [22,[26][27][28][30][31][32][33][34][35][36]. We propose an alternative time-dependent approach to address the issue of ZBW, by exploring the features of the probability density at very long-times (t t F ), which allows us to describe the dynamics using simple asymptotic formulas.…”

“…In fact, the ZBW effect [21,22], and Klein-tunneling have now become accessible to experiments [23,24], and also the importance of transient nature of the ZBW has been stressed out [25]. Theoretical models dealing with Gaussian wavepacket dynamics have proven to be powerful methods to study transient quantum wave dynamics and ZBW phenomena in physical systems such as semiconductors [26][27][28][29], monolayer and bilayer graphene [22,25,[30][31][32][33], silicene [34,35], and phosphorene [36]. Recently, a signature of the ZBW effect in the particle density has been reported in a model involving the dynamics of a massive Dirac particle in the vicinity of a black hole [37], using an initial Gaussian wave.…”

Dynamics of a quasiparticle in theα-T3model: role of pseudospin polarization and transverse magnetic field onzitterbewegung

“…However, a ray of hope was shown in 2005 when Zawadki [2] argued that a narrow gap semiconductor not only can host the intriguing phenomenon ZB but also the associated length scale can be enhanced up to five orders higher than that in vacuum. As a result, subsequent years witnessed immense interest in ZB in numerous systems [3] including spin-orbit coupled two dimensional (2D) electron/hole gases [4][5][6][7][8][9][10][11], superconductors [12], sonic crystal [13], photonic crystal [14,15], carbon nanotube [16], graphene [17][18][19][20][21], other Dirac materials [22][23][24] and ultra-cold atomic gases [25][26][27][28].…”

Resonant longitudinalZitterbewegungin zigzag graphene nanoribbons

“…Although this effect has drawn significant theoretical attention from the perspective of relativistic theory [1,2] and for the understanding of fundamental physics regarding electron structure [3] and spin [4], its observation has remained an experimental challenge for a long time. Recently, it has been realized that a large class of noncentrosymmetric condensed matter systems [5,6] like nanowires [7][8][9], two dimensional electron gas [10], and honeycomb lattices [11,12] (e.g., graphene, silicene [13], MoS 2 [14], etc. ), surfaces of topological insulators [15,16], photonic crystals [17], and cold atom gases [18][19][20] can be described by a Dirac-like equation and hence becomes instrumental for the experimental observation of Zitterbewegung.…”