Identifying Electronic Transitions of Defects in Hexagonal Boron Nitride for Quantum Memories

Abstract

A quantum memory is a crucial keystone for enabling large‐scale quantum networks. Applicable to the practical implementation, specific properties, i.e., long storage time, selective efficient coupling with other systems, and a high memory efficiency are desirable. Though many quantum memory systems are developed thus far, none of them can perfectly meet all requirements. This work herein proposes a quantum memory based on color centers in hexagonal boron nitride (hBN), where its performance is evaluated based on a simple theoretical model of suitable defects in a cavity. Employing density functional theory calculations, 257 triplet and 211 singlet spin electronic transitions are investigated. Among these defects, it is found that some defects inherit the Λ electronic structures desirable for a Raman‐type quantum memory and optical transitions can couple with other quantum systems. Further, the required quality factor and bandwidth are examined for each defect to achieve a 95% writing efficiency. Both parameters are influenced by the radiative transition rate in the defect state. In addition, inheriting triplet‐singlet spin multiplicity indicates the possibility of being a quantum sensing, in particular, optically detected magnetic resonance. This work therefore demonstrates the potential usage of hBN defects as a quantum memory in future quantum networks.

The hBN Defects Database: A Theoretical Compilation of Color Centers in Hexagonal Boron Nitride

“…However, the former still requires zero-field splitting and ODMR simulations for confirmation, while the latter has been added to this database through the performance metrics developed by our prior work. 50 As a consequence, this database can also be employed to pinpoint potential candidates suitable for quantum applications.…”

“…We focus especially on the triplet and singlet states as their electronic structures can be applied not only as a single photon source but also for quantum sensing [16][17][18]51 and quantum memory applications. 50,52 For quantum sensing, a recent example is the negatively charged boron vacancy. Its intrinsic triplet state allows it to have the splitting at m s = 0 and ±1, which supports the optically detected magnetic resonance (ODMR) measurement.…”

“…This database is openly accessible via . Some subfigures are adapted from ref available under a CC-BY 4.0 license. Copyright 2024 Cholsuk et al Some subfigures are adapted with permission from ref Copyright 2023 American Chemical Society.…”

Comparative Study of Quantum Emitter Fabrication in Wide Bandgap Materials Using Localized Electron Irradiation

“…Quantum emitters in solid-state crystals have garnered considerable attention, driven by the rapid advancement of quantum technology applications such as quantum computing, quantum communication, and quantum sensing. − The discovery of quantum emitters based on defects in wide bandgap materials has significantly advanced this field. − Quantum emitters have been used in a wide variety of applications, most prominently in magnetometry and imaging, , but also in quantum key distribution, , fundamental quantum physics tests, thermometry, pressure sensing, quantum computing, quantum memories, − and as nodes in a quantum network …”

Efficient light propagation algorithm using quantum computers

“…Recently, major breakthroughs toward outstanding performance in computation, communication, and sensing by leveraging quantum properties have been demonstrated. Although many quantum systems are still under ongoing investigation [1][2][3][4][5][6][7], quantum computers [8,9] have potentially performed tasks or measurements, that cannot be done classically, e.g., in quantum sensing [10,11], quantum communication [12,13], and interferometry [14].…”