Near-zero thermal expansion of GeNb18O47 ceramic

Near-zero thermal expansion (NZTE) materials have important scientific significance and several potential applications. In this work, a NZTE GeNb18O47 ceramic has been successfully synthesized by the solid-state method, and its phase, structure, expansion properties, and NZTE mechanism were investigated. Results show that the pure phase GeNb18O47 ceramic is successfully obtained, and the crystal structure is composed of NbO6 octahedron and Nb/GeO4 tetrahedron. GeNb18O47 shows a near-zero linear coefficient of thermal expansion (CTE) of 1.23 × 10−6 °C−1 (−100–400 °C), which is caused by negative thermal expansion (NTE) originating from the rotational coupling of NbO6 octahedron and Nb/GeO4 tetrahedron. In addition, GeNb18O47 is a NZTE semiconductor with a band gap of 3.05 eV, which has great application value in integrated circuits, and chip manufacturing.