Engineering van der Waals heterostructures for dispersion-selective meV-scale quantum sensing

Abstract

Quantum sensing of meV-scale scattering and absorption of impinging particles with electrons in solid state detectors is a challenging technological advancement with the potential to enable breakthroughs in quantum information applications and studies of fundamental physics. However, a key obstacle for current sensing schemes is the difficulty in distinguishing the signals from particles of interest and from intrinsic excitations, like phonons or magnons. Here we propose a technique to selectively detect impinging particles based not only on their imparted energy, but specifically by their dispersion relations. By harnessing interfacial orbital hybridization in van der Waals heterostructures of Dirac materials, interlayer charge transfer may be promoted only for pre-selected impinging particles of interest. Using first-principles density functional theory (DFT) calculations of heterostructures of the layered Dirac materials ZrTe5 and HfTe5, we examine the effects of strain and layer number for successfully tuning orbital hybridization in their electronic structure. We demonstrate a proof-or-principle feasibility study for using Dirac materials to construct dispersion filters to be leveraged for next-generation meV-scale quantum sensors.

Figures (9)

• Figure 1: Simplified Real-space schematic of detector setup. An impinging particle produces excited electrons and holes in the top layer. An excited electron rapidly transfers to the bottom layer only if the impinging particle had the correct dispersion relations. Otherwise carriers remain in the top layer and recombine.
• Figure 2: Reciprocal space (top panels) and real space (bottom panels) schematics of proposed detection scheme. A valence electron at the VBM in layer 1 (top layer in real space panels) is excited to a hybridized state in the conduction band with orbital character spanning both layers. The excited electron then decays into the CBM and occupies an orbital that is entirely in layer 2 (bottom layer in real space panels). This process can only occur if the electron was excited by an impinging particle with the correct dispersion relations (combination of transferred energy ($\omega$) and transferred momentum ($\mathbf{q}$) (center reciprocal space panel)
• Figure 3: Crystal structures of (a) monolayer ZrTe$_{5}$ and (b) monolayer HfTe$_{5}$ and their corresponding band structures (c) and (d), respectively.
• Figure 4: Crystal structures and electronic structures of various ZrTe$_{5}$-HfTe$_{5}$ heterostructures: (a,d) monolayer ZrTe$_{5}$ with monolayer HfTe$_{5}$, (b,e) bilayer ZrTe$_{5}$ with bilayer HfTe$_{5}$, and (c,f) monolayer ZrTe$_{5}$ with monolayer HfTe$_{5}$ under 3% tensile strain. The band structures are colored according to orbital projections onto each layer with purple indicating wavefunctions primarily confined to ZrTe$_{5}$ and green indicating wavefunctions primarily confined to HfTe$_{5}$. Lighter colored and white areas have hybridized wavefunctions with contributions from orbitals that span both layers.
• Figure S1: The band structures of monolayer and bulk MoS$_{2}$. (a) In the band structure for monolayer MoS$_{2}$ the valence band maximum (VBM) and conduction band minimum (CBM) are both located at the high symmetry $\mathrm({K}$ point. (b) The orbital character of the VBM is entirely in-plane (orbitals are illustrated in green). (c) In the band structure for bulk MoS$_{2}$ the VBM is located at the high symmetry $\mathrm({\Gamma}$ point and CBM is located at a minimum in the $\mathrm({\Lambda}$ valley. (d) The orbital character of VBM and CBM in bulk MoS$_{2}$ includes strong out-of-plane contributions (orbitals are illustrated in purple). This leads to interlayer hybridization.