Progress ｜ The discovery and mechanism of liquid atom in metal glass

Depending on the state of atomic movement, material can usually be divided into three states: solid, liquid, and gas. There are obvious differences between three state. For example, liquid water and solid ice. The boundary. However, some of the latest studies challenged our basic understanding of the material. In extreme conditions or special systems, single -phase substances can be in a strange state of both solid and liquid state, that is, there are atoms in the solid that can spread like liquids to spread like liquids. Essence For example, under the high temperature and high pressure (such as the inside of the ice giant planet such as heaven and Neptune), it will be in a strange super ionic state. The oxygen atom is fixed to vibrate near the balance position, and the hydrogen atom can spread freely as in the liquid. The core of the earth may also be in a super ionic state, and iron atoms form a solid ground nucleus, and light elements such as hydrocarbons can flow quickly. The more secure and efficient omnidirectional lithium batteries we are pursuing, one of the core issues is that lithium ions can quickly shuttle as fast as liquid electrolytes in solids. Therefore, the phenomenon of liquid in this solid is attracting more and more attention from scientists in different fields.

Glass is a special solid material, which has typical solid characteristics such as super strong, super hard, and densely stacked. At the same time, it has an atomic structure like liquid disorderly. It is a typical complex system. Although glass materials can be seen everywhere in life, and humans have been using glass for thousands of years, scientists still cannot give clear glass micro -structures and dynamic images. Although the glass has a micro -structure similar to liquid, people generally believe that its internal atoms have lost the ability to move as large as liquid, and glass is usually called frozen liquid.

Recent A variety of dynamic research methods such as dynamic mechanics experiments, nano -pressure marks and molecular dynamics simulation, and found that the tightly accumulated glass solids such as metal glass have inherited high -temperature liquid dynamic behavior. These liquid atoms have not been frozen, and they can still spread quickly at room temperature. The effective viscosity is only 10 pack seconds, which is at least 6 magnitude lower than the viscosity of metal glass. This discovery broke through the traditional micro -image of the glass, revealing the nature of part of the metal glass and the nature of some liquid.

Directly observing the movement of atoms in the experiment is a very difficult thing. In this study, the experimental personnel used dynamic stimulation to study the atomic movement inside the glass. When the frequency of external disturbance is equivalent to the frequency of internal atom movement, resonance absorption occurs with the outer field, so that the characteristics of the feature can be measured in the experiment. Researchers focus on the loss peaks of metal glass at low temperature, that is, fast relaxation of Yufeng (Figure 1). This dynamic model is faster than the α relaxation of the large -scale motion of atomic in the glass observed in the past and the β -relaxation corresponding to the corresponding local movement, that is, there are atoms that are faster in metal glass that exceeds the faster movement of traditional cognition. Essence The measurement of a large number of dynamic activation energy of different systems shows that the activation capacity of fast and relaxing is consistent with the activation of high -temperature liquid dynamics (Figure 2). Compared with the relaxation time of different relaxation processes, it is also found that the dynamics of high temperature liquid and the fast relaxation in glass solids meet the same Arrhenius relationship (Figure 3), which means that during the cooling process of liquid It is not completely frozen, some atoms can continue the Arrhenius relationship of high -temperature liquid to the glass solid, resulting in the ultra -fast stagnation of the glass solid room temperature and the fast -acting peak at low temperature. Further, researchers used molecular dynamics simulation to characterize the movement characteristics and inheritance process of liquid atoms in the LA-A system. Studies have found that AL atoms with a local disorderly topology environment at room temperature will occur in long -range diffusion behaviors similar to melting, and present the characteristics of chain -like motion (Figure 4). This chain -shaped motion has been produced in high temperature liquid (Figure 5), and it will become more and more significant as the temperature decreases, until it is manifested in the glass solid as a fast dynamic mode at low temperature, which means that the inheritance of the liquid atomic inheritance is essentially It is the inheritance of the chain -like motion mode.

The study of liquid atoms in metal glass deepen our understanding of the essence of glass, that is, the glass state is actually a part of solid state, and some of them are a strange state of liquid state. This new physical image not only clarifies the origin of the rapid relaxation mode of glass at low temperature, but also helps build the dynamics-nature relationship of glass. For example, these liquid atoms can cause obvious stagnation at room temperature at metal glass, and are likely to be closely related to the plastic deformation of metal glass. In addition, the disorderly correlation between the metal glass -like atom and the structure of the structure will also inspire the super fast diffusion in other solid substances, such as the origin of the structure of the ultra -ion state and the migration of solid electrolyte ions.

Related research results are titled "liquid-like atoms in dense-packed solid grasses". On August 15, 2022One author.For details, see the link https://www.nature.com/articleS/s41563-022-01327-w.The study was the National Natural Science Foundation of China (52192600, 61888102, 11790291, 52031016, 51631003), Guangdong Natural Science Foundation (2019B030302010), the Strategic Pilot Science and Technology Special (XDB30000000) of the Chinese Academy of Sciences (2018YFA0703603), and the post -doctoral fund fund(2020tq0346, 201M693372) support.

Figure 1: Dynamic spectrum detects the fast relaxation process

Figure 2: The correlation of the activation energy of fast relaxation and high temperature liquid

Figure 3: relaxed map of YCO metal glass

Figure 4: 300 K recognition and representation of liquid atoms in ALLA metal glass

Figure 5: The inheritance process of the chain diffusion in the ALLA system

Edit: yellow water machine

- END -