C2DB

Official Resources

• Homepage: https://cmr.fysik.dtu.dk/c2db/c2db.html
• Documentation: https://cmr.fysik.dtu.dk/c2db/c2db.html
• Source Repository: Data available via ASE/ASR
• License: Open Data

Overview

C2DB is a highly curated database of two-dimensional materials calculated using the Atomic Simulation Environment (ASE) and the GPAW electronic structure code. It systematically classifies and characterizes thousands of 2D monolayers, calculating a wide range of properties including stability, stiffness, topological invariants, and excited state properties (GW band gaps, excitons).

Scientific domain: 2D materials, high-throughput DFT, many-body perturbation theory
Target user community: 2D materials researchers

Capabilities (CRITICAL)

• Database: >4000 2D materials.
• Stability: Dynamical stability (phonons) and thermodynamic stability (convex hull).
• Electronic: PBE and HSE06 band structures, GW quasiparticle gaps.
• Optical: BSE absorption spectra (excitons).
• Topology: Berry phases, Chern numbers, Z2 invariants.
• Magnetic: Heisenberg exchange parameters, magnetic anisotropy.
• Mechanical: Elastic stiffness tensors.

Sources: C2DB website, 2D Mater. 8, 025021 (2021)

Inputs & Outputs

• Input formats: Searchable web interface
• Output data types: ASE database format (.db), JSON

Interfaces & Ecosystem

• ASR (Atomic Simulation Recipes): The workflow engine used to generate C2DB.
• GPAW: The primary calculation code.
• ASE: The underlying framework.
• MyQueue: Used for job scheduling.

Workflow and Usage

1. Web: Browse materials at cmr.fysik.dtu.dk.
2. Python: Download the database via ase:

   from ase.db import connect
   db = connect('c2db.db')
   

Performance Characteristics

• High-fidelity data (GW/BSE)
• Focus exclusively on 2D materials

Application Areas

• Discovery of new 2D semiconductors
• Topological insulators
• Single-photon emitters
• Catalysis

Community and Support

• Developed by CAMD (Thygesen Group) at DTU
• Open access

Verification & Sources

Primary sources:

1. Homepage: https://cmr.fysik.dtu.dk/c2db/c2db.html
2. Publication: S. Haastrup et al., 2D Mater. 5, 042002 (2018); M. N. Gjerding et al., 2D Mater. 8, 025021 (2021)

Confidence: VERIFIED

Verification status: ✅ VERIFIED

• Website: ACTIVE
• Documentation: COMPREHENSIVE
• Source: OPEN (Recipes via ASR)
• Development: ACTIVE
• Applications: 2D materials database, GW/BSE