Chiral phonons entangled with multiple Hall effects and unified convention for pseudoangular momentum in 2D materials

Abstract

Recently, a series of two-dimensional (2D) nonmagnetic layered materials XSi2Y4 (X=transition metals; Y=pnictogens) having similar crystal structures with transition-metal dichalcogenides (TMDs) were proposed for their potential application value. Like TMDs, we propose that chiral phonon involved valley-selective optical circular dichroism can be also obtained in XSi2Y4, and it can be further entangled with multiple Hall effects. However, it is difficult to compare such effect between XSi2Y4 and TMDs due to the non-unified conventions for pseudo-angular momentum (PAM) in the previous studies. Here we use MoSi2As4 and MoS2 as examples to establish unified convention for both phonon PAM and electronic PAM, together with showing their similarities and differences in crystal structure, band structures and valley-selective optical circular dichroism. In particular, we find in MoSi2As4, the chiral phonon emission/absorption, the spin, the valley and the transverse Hall current, can be modulated by changing either the energy or the handedness of the incident light, which show better performance than TMDs.

8 pages, 4 figures

References in corpus (10)

• Valley polarization in MoS2 monolayers by optical pumping
• Tightly bound excitons in monolayer WSe2
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Exceptional piezoelectricity, high thermal conductivity and stiffness and promising photocatalysis in two-dimensional MoSi2N4 family confirmed by first-principles
• Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
• High intrinsic lattice thermal conductivity in monolayer MoSi${}_2$N${}_4$
• Semiconductor-to-metal transition in bilayer MoSi${}_2$N${}_4$ and WSi${}_2$N${}_4$ with strain and electric field
• Strain effects on monolayer MoSi2N4: ideal strength and failure mechanism
• Chiral phonons and pseudo-angular momentum in non-symmorphic systems
• Two-dimensional MoSi2N4: An Excellent 2D Semiconductor for Transistors

Cited by in corpus (3)

• Transverse Peierls Transition
• Physics of Phonons in Systems with Approximate Screw Symmetry
• Advancements in Entangled Photon Pairs in 2D Van der Waals Materials for On-chip Quantum Applications