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CN-121377028-B - Ferroelectric metal, preparation method and application thereof

CN121377028BCN 121377028 BCN121377028 BCN 121377028BCN-121377028-B

Abstract

The invention provides ferroelectric metal, a preparation method and application thereof. The ferroelectric metal of the present invention is composed of a cubic silicon carbide crystal and a doping element doped therein, the concentration of the doping element being greater than or equal to 1×10 18 cm ‑3 . The material of the invention can be prepared by adopting a chemical vapor deposition method, a high-temperature solution growth method, a solid-phase sintering method, a pulse laser deposition method and the like. The ferroelectric metal of the invention has great application value in the fields of high-performance energy converter, high-sensitivity sensor, low-power micro-electro-mechanical system (MEMS), next-generation multifunctional electronic device and the like because the conductivity, ferroelectric switching characteristic and piezoelectric electromechanical coupling characteristic of the metal are integrated.

Inventors

  • CHEN XIAOLONG
  • LI HUI
  • YANG YUNFAN
  • LIU ZHAOLONG
  • WANG WENJUN

Assignees

  • 中国科学院物理研究所

Dates

Publication Date
20260508
Application Date
20251113

Claims (8)

  1. 1. The application of the composite material as ferroelectric metal is characterized in that the composite material consists of cubic silicon carbide crystals and doping elements doped in the cubic silicon carbide crystals, wherein the concentration of the doping elements is more than or equal to 1 multiplied by 10 18 cm -3 ; The doping element is selected from one or more of N, P, as, sb, al, ti, B, ti, V, cr, mn, fe, co, ni and Cu elements.
  2. 2. The use according to claim 1, wherein the composite exhibits a metallic behavior in relation to the resistivity of the composite material with a room temperature resistivity of 0.0001-1 m Ω -cm.
  3. 3. Use according to claim 1, wherein the composite material is in the form of a single crystal, polycrystalline powder, film or two-dimensional material.
  4. 4. The use of claim 1, wherein the composite material has room temperature ferroelectricity.
  5. 5. The use according to claim 1, wherein the composite material has a piezoelectric effect.
  6. 6. The use according to claim 1, wherein the composite material has an inverse piezoelectric effect.
  7. 7. The use of any one of claims 1 to 6, wherein the composite material is used in a transducer, a sensor, a microelectromechanical system, an information storage, an energy storage, or an electro-optic modulator.
  8. 8. The use according to any one of claims 1 to 6, wherein the composite material is produced by a liquid phase method, a solid phase method, a chemical vapor deposition method or a physical vapor transport method, and comprises reacting a silicon source, a carbon source and a doping element on a substrate by applying energy in the presence of an atmosphere or a raw material containing the doping element, or combining a cubic silicon carbide raw material with the doping element to form the doped cubic silicon carbide crystal.

Description

Ferroelectric metal, preparation method and application thereof Technical Field The invention belongs to the field of novel electronic functional materials, and particularly relates to ferroelectric metal, a preparation method and application thereof. Background Ferroelectric materials are functional materials that can generate spontaneous polarization when an external electric field is zero, and whose spontaneous polarization direction can be reversed by the external electric field, and play an important role in a plurality of electronic devices such as nonvolatile memories, sensors, piezoelectric drivers, and the like. However, conventional ferroelectricity is considered to be mutually exclusive with metal conductivity because a high concentration of free electrons in the metal annihilates the polarized electric dipoles inside the material by electrostatic shielding effect, thereby destroying the macroscopic polarized field, i.e., the long Cheng Tiedian order. Thus, most ferroelectric materials found to date are insulators or semiconductors. This traditional perception was theoretically challenged in 1965. Anderson and Blount（P. W. Anderson, E. I. Blount, Symmetry considerations on martensitic transformations: "Ferroelectric"metals? Physical Review Letters. (1965) 14, 217–219.）, which for the first time have proposed the concept of "ferroelectric metals", theorize that certain metallic species may lose inversion symmetry centers through structural phase transitions, thereby producing reversible spontaneous polarization, i.e., both metallic conductivity and ferroelectricity. However, this prediction has always lacked firm experimental evidence in the next near half century. Until 2013, researchers have first experimentally confirmed the presence of polar metals. They found that LiOsO 3 structural phase transformation from the central symmetric space group (R-3 c) to the non-central symmetric space group (R3 c) occurs below 140: 140K and that both Materials remain metallic before and after this phase transformation (Nature Materials, 2013, 12, 1024). This work demonstrates the presence of "polar metals" with polar structures, but there is no direct experimental data demonstrating the "ferroelectric metal" character (macroscopic spontaneous polarization that can be reversed by an electric field). For this reason, it has been known for a long time that ferroelectricity and metallic cannot coexist in the field of aggregate physical and material research. However, the polar metallic materials such as LiOsO 3, which have been found at present, still have significant limitations, severely restricting their practical application: The problem of element toxicity is that Os (osmium) element in LiOsO 3 has toxicity and does not accord with the development trend of green and environment-friendly materials. Performance bottlenecks-its room temperature resistivity (about 1.5 m Ω cm) is much higher than that of conventional metals (e.g., silver, room temperature resistivity of 0.00168 m Ω cm), resulting in its poor efficiency in conductive applications. Preparation and size limitations reported materials are small in size (e.g., on the order of 200 μm) and are difficult to meet the requirements of macroscopic device fabrication. Therefore, there is an urgent need in the art to develop a novel ferroelectric metal material that is truly non-toxic, has lower resistivity, and is easy to be prepared in a large scale, so as to promote the practical application of the material in the fields of transducers, sensors and microelectromechanical systems, information storage, energy storage, electro-optic regulation and control, and the like. Cubic silicon carbide (3C-SiC) has been attracting attention as an important third generation wide band gap semiconductor material, with its high thermal conductivity, high critical breakdown electric field, excellent chemical stability, and excellent mechanical properties, and has good compatibility with existing semiconductor manufacturing processes. Currently, doping studies of the opposite silicon carbide are mainly focused on regulating its conductivity type (n-type or p-type) for power electronics, or on preparing diluted magnetic semiconductors by introducing transition metals (such as Mn, fe, etc.). There is no disclosure or technical data at present that intrinsic ferroelectricity can be induced by doping the opposite silicon carbide, and it is not disclosed that efficient coexistence of ferroelectricity and metals therein can be achieved. In the prior art, doped cubic silicon carbide is only considered as a conductor, semiconductor or magnetic material, and its application potential as ferroelectric metal is not recognized at all. Disclosure of Invention Aiming at the problems and the defects existing in the prior art, the invention aims to overcome the defects of lack of ferroelectric metal materials, direct experimental data for confirming the existence of ferroelectric metals and th