Cage mesh structure calcium niobium alloy superconducting material

Abstract

The invention discloses a calcium-niobium alloy superconducting material with a cage mesh structure, and belongs to the technical field of new superconducting materials. According to the technical scheme, the molecular formula of the calcium-niobium alloy superconducting material of the cage-mesh structure is CaNb5, the calcium-niobium alloy superconducting material of the cage-mesh structure is of a cage-mesh lattice structure, a cage-mesh lattice structure layer is mainly formed by stacking niobium atoms, metal calcium atoms are located at the center positions of the niobium atoms of the cage-mesh layer, the crystal space group of the calcium-niobium alloy superconducting material is P6 / mmm (No.161), the point group is D6h, and the crystal space group of the calcium-niobium alloy superconducting material is P6 / mmm (No.161). The calcium-niobium alloy superconducting material with the cage-mesh structure is stable in structure under normal pressure, and the superconductivity of the calcium-niobium alloy superconducting material with the cage-mesh structure can be effectively adjusted and enhanced by applying external pressure or / and doping carriers. The cage-mesh-structure calcium-niobium alloy superconducting material designed by the invention has the advantages of simple structure, high superconducting transition temperature, adjustable pressure, rich properties and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of new niobium-based alkaline earth metal alloy superconducting materials, and particularly relates to a kagome structure calcium niobium alloy superconducting material. Background Art

[0002] In recent years, kagome lattice materials have attracted great interest from researchers at home and abroad due to their unique geometric structures. So far, various types of kagome lattice materials have been theoretically predicted or experimentally prepared. While kagome lattice materials exhibit geometric frustration characteristics in structure, they also show different structures and various electronic characteristics, thus well reflecting the differences in atomic composition and geometric arrangement. They contain various special electronic states, such as flat bands (FB), van Hove singularities, and Dirac fermions, etc., which also make them excellent platforms for studying exotic superconductivity and topological properties. The rich electronic structures of kagome lattice materials show interesting behaviors in superconducting and non-trivial topological environments, such as spin liquid, charge density wave, unconventional charge order, and anomalous Hall effect, etc. The superconductivity of kagome lattice materials has also been widely discussed, including Fe 3 Sn 2 compounds (non-superconducting), CoSn-type families ( T c <1.9 K), AV 3 Sb 5 families (0.9K< T c <2.8 K), AV 6 Sb 6 families (non-superconducting) and LaRu 3 Si 2 compounds ( T c <7 K), MgB 3 etc. Kagome lattice materials have rich physical properties. Therefore, it is of great research significance to discover more kagome lattice materials and regulate their rich material states. For example, the coexistence of topological order and superconductivity in kagome lattice materials provides more opportunities for realizing topological superconductors and studying the complex interactions between superconductivity and non-trivial topological states. Although many research groups have successively explored a number of kagome structures, the experimental implementation and application of materials are still limited, mainly due to the scarcity of kagome materials. Therefore, predicting more ratios or types of kagome materials is important. Summary of the Invention

[0003] The technical problem solved by the present invention is to provide a kagome structure calcium niobium alloy superconducting material with a simple structure, a high superconducting transition temperature, adjustable pressure, and rich properties.

[0004] The present invention adopts the following technical solutions to solve the above technical problems. A kagome-structured calcium niobium alloy superconducting material, characterized in that: the molecular formula of the calcium niobium alloy superconducting material is CaNb 5 , having a kagome lattice structure, the kagome lattice structure layer is mainly composed of stacked niobium atoms, and the metallic calcium atoms are located at the center of the niobium atoms in the kagome layer. The crystal space group of the calcium niobium alloy superconducting material is P6 / mmm (No. 161), and the point group is D 6h . The kagome-structured calcium niobium alloy superconducting material has a stable structure under normal pressure, and the superconductivity of the kagome-structured calcium niobium alloy superconducting material can be effectively adjusted and enhanced by applying external pressure or / and carrier doping methods.

[0005] Furthermore, the intrinsic superconducting transition temperature of the kagome-structured calcium niobium alloy superconducting material is 10.1 K. Under the action of applying external pressure, the superconducting transition temperature of the kagome-structured calcium niobium alloy superconducting material is increased to 12.8 K.

[0006] Compared with the prior art, the present invention has the following advantages and beneficial effects: The designed kagome-structured calcium niobium alloy superconducting material of the present invention has the characteristics of simple structure and superconducting transition temperature; the superconducting transition temperature of the kagome-structured calcium niobium alloy superconducting material can be finely tuned by applying external pressure or / and carrier doping methods; the kagome-structured calcium niobium alloy superconducting material also has some other novel physical properties, such as having flat bands, multiple Dirac points and non-trivial topological physical properties. The designed kagome-structured calcium niobium alloy superconducting material of the present invention has the advantages of simple structure, high superconducting transition temperature that can be adjusted by pressure, and rich properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of the crystal structure of a kagome-structured calcium niobium alloy superconducting bulk. The upper figure is a top view, and the lower figure is a side view. The niobium atom layer is a kagome lattice, composed of six-membered rings and triangular lattices, and the center of the kagome atom layer is a metallic calcium atom.

[0008] Figure 2 is a graph of pressure-superconducting transition temperature of a kagome-structured calcium niobium alloy superconducting bulk. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following further elaborates on the above content of the present invention in detail through examples, but it should not be understood that the scope of the above subject matter of the present invention is limited to the following examples. Any technology implemented based on the above content of the present invention belongs to the scope of the present invention.

[0010] The present invention constructs a kagome-structured calcium niobium alloy superconducting material composed of alkaline earth metal calcium and niobium. The molecular formula of the kagome-structured calcium niobium alloy superconducting material is CaNb 5, having a kagome lattice structure, the kagome lattice structure layer is mainly composed of stacked niobium atoms, and metallic calcium atoms are located at the central positions of the niobium atoms in the kagome layer. The crystal space group is P6 / mmm (No. 161), and the point group is D 6h . The preparation of the kagome-structured calcium niobium alloy superconducting material can be achieved using traditional material preparation methods, such as hybrid physical-chemical vapor deposition method, powder method, solid-state reaction method, electron beam evaporation method, co-evaporation method, sputtering method, etc.

[0011] In this invention, the superconducting transition temperature of the material is tested by using the advanced superconductor density functional method in the industry, and the superconducting transition temperature of the kagome-structured calcium niobium alloy superconducting material is regulated by applying external pressure and carrier doping. Through the measurement of the superconductivity of the kagome-structured calcium niobium alloy superconducting material, the superconducting transition temperature of this material is determined, providing important theoretical basis and specific structural model data for the further preparation of superconducting materials with simple structure and high transition temperature.

[0012] The kagome-structured calcium niobium alloy superconducting material described in this invention is structurally stable under normal pressure, and its intrinsic superconducting transition temperature is 10.1K. By applying external pressure or / and carrier doping, the superconductivity of the kagome-structured calcium niobium alloy superconducting material can be effectively regulated and enhanced. Especially under the action of external pressure, the superconducting transition temperature of the kagome-structured calcium niobium alloy superconducting material is increased to 12.8K.

[0013] As Figure 1 shown, it is the crystal structure of the kagome-structured calcium niobium alloy superconducting material designed by this invention, which exhibits many excellent physical properties, such as flat bands, multiple Dirac points, non-trivial topological properties, etc. The kagome-structured calcium niobium alloy superconducting material designed by this invention has the characteristics of simple structure, clear superconducting transition temperature and adjustable external stress, and rich properties, and can be applied to superconducting materials and topological materials.

[0014] In addition, alloy materials with the same structure as the kagome-structured calcium niobium alloy discovered in this invention may also exhibit superconductivity and topology, and can be applied to fields such as superconducting materials and topological materials.

[0015] The above embodiments describe the basic principles, main features and advantages of this invention. Those skilled in the art should understand that this invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of this invention. Without departing from the scope of the principles of this invention, this invention will have various changes and improvements, and these changes and improvements all fall within the scope of protection of this invention.

Claims

1. A cage-structured calcium-niobium alloy superconducting material, characterized in that: The molecular formula of the calcium-niobium alloy superconducting material is CaNb5, and it has a cage lattice structure. The cage lattice structure layer is mainly composed of niobium atoms stacked together, and the metal calcium atom is located at the center of the niobium atom in the cage layer. The crystal space group of the calcium-niobium alloy superconducting material is P6 / mmm (No.161), and the point group is D 6h The cage-structured calcium-niobium alloy superconducting material has a stable structure under normal pressure, and the superconductivity of the cage-structured calcium-niobium alloy superconducting material can be effectively adjusted and enhanced by applying external pressure and / or carrier doping.

2. The cage-structured calcium-niobium alloy superconducting material according to claim 1, characterized in that: The intrinsic superconducting transition temperature of the cage-structured calcium-niobium alloy superconducting material is 10.1K. Under the action of external pressure, the superconducting transition temperature of the cage-structured calcium-niobium alloy superconducting material is increased to 12.8K.

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