Solid-state physics

Solid state physics is a branch of the scientific study of the microscopic and macroscopic properties of things that take a solid form (that is, are not gases or liquids). Closely related to condensed matter physics, this field of science is particularly interested in the new properties that form when many small atoms are placed close together to form a larger solid object. It is a field of study with great importance in the development of many forms of modern technology. It also has applications in several other scientific fields, including chemistry, engineering, biology, medicine, and crossover fields such as bioengineering and biochemistry. Research efforts in solid state physics have led to such technological breakthroughs as the semiconductors that are an integral part of many modern electronic devices and many developments that have earned researchers Nobel Prizes in physics.

Background

The study of solid materials is one of the oldest forms of scientific inquiry, although it was not always known by that name. Two of the earliest areas studied and wondered about by humankind were the sky and the earth. The study of the sky became the field of astronomy, while the early efforts to understand the rocks and other objects on earth became what is now known as solid state physics.

Physics is defined as the study of matter and energy and the ways in which they interact. There are several different areas of study under the broader term of physics. These include atomic physics, or the study of the properties of the smallest bits of matter (atoms); nuclear physics, or the study of how atomic particles interact to form nuclear reactions, radioactivity, etc.; and a host of sub-areas of study such as electromagnetism and thermodynamics. One of the largest fields of study in this area is solid state physics, which is concerned with how atoms interact to form solid substances such as crystals, metals, etc., and the properties of these solids.

While people were able to examine and study the solid objects around them for centuries, they were limited by the tools available to them for identifying specific visible details about the objects. It was not until the nineteenth century that scientists had the tools and technology needed to begin to connect these facts and truly understand why solid objects form and behave as they do. The development of the modern microscope in the seventeenth century began the process that came to full fruition when scientists developed theories such as electromagnetism and thermodynamics in the early 1800s. These two theories, which explained how the forces of magnetism and heat affect matter, were important in helping scientists begin to study the ways atoms combine to form solids and how other forces of physics affect this.

Solid state physics as a science experienced major growth between the 1920s and the 1960s, when many new developments were funded by governments driven by the desire for military superiority during World War II (1939–1945). After that time, the study of solid state physics has often been divided into many sub-fields or simply referred to by different names. These sub-fields included condensed matter, quantum optics, biological physics, and materials science. Research in condensed matter physics also expanded into areas such as quantum materials and topological materials with potential applications in advanced electronics, quantum computing, quantum technologies, and advanced semiconductor devices. Nevertheless, the discoveries made in solid state physics remain crucial to life in the twenty-first century. Understanding how atoms combine to form solids made possible technologies such as transcontinental phone lines, computers, cell phones, and other electronic devices.

Overview

Solid state physics is a diverse field because solids are very diverse in makeup. Some solids have a relatively random arrangement of atoms that form weak bonds; these form solids such as wood, which is a weak conductor of heat and electricity. Some solids are made up of atoms that form close bonds with their near neighbors but the overall pattern formed by the atoms is still random; these are called amorphous solids and include substances such as glass. The largest group of solids is crystalline solids; the atoms in these substances, which make up 90 percent of the known solids, form structures with a regular order and arrangement and include metals and minerals. One crystalline solid, silicon, plays a key role in transistors and semiconductors that make modern electronics possible. In the 2020s, many countries increased investments in semiconductor research and manufacturing to strengthen computer chip production and supply chains.

The study of solid state physics involves determining the properties of the substances and how they interact. Knowing how the atoms in a substance will interact helps researchers to find new ways to use the solids. For instance, some solids are made of hard matter, such as crystals, metals, glass, and rubber. Others are made of soft matter; these include some liquid crystals and the proteins, membranes, and other substances that make up biological solids.

Solid state physicists examine how the atoms are combined in a substance to learn answers to questions such as why it is hard or soft, why it is shiny or dull, or why it is clear or opaque. They conduct experiments to test how both hard and soft matter are affected by the influence of heat and cold, electricity and magnetic fields, radiation, and other factors. Knowing why solids are the way they are and how they can be changed allows researchers to capitalize on the properties of the solids and sometimes to manipulate them to create new ways of using them.

The study of solid state physics is important because it is a key to understanding many things about the world. Armed with this understanding, researchers can envision new uses for existing solids and engineer new ways that greatly enhance life in the twenty-first century. This expanding knowledge and understanding also enables discoveries in other areas of science and supports growth in areas such as biology and health that have the potential to improve humans’ quality of life in many ways.

Bibliography

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