Johannes Hendrik van der Merwe (28 February 1922 - 28 February 2016) was a South African mathematician and physicist. The Frank–Van der Merwe crystal growth model carries his name and he was awarded numerous South African academic prizes. He is sometimes referred to as the "Father of Epitaxy". His research is seen as fundamental to applications in communication technology.
Education and early life
Van der Merwe was born on 28 February 1922 to Dorslandtrekkers Johannes Marthinus van der Merwe and Catharina Margaretha van der Merwe in Humpata, Angola. Although his parents both came from large families—his father had four siblings and his mother had five siblings—he was an only child.
In 1928, he and his family moved to South West Africa. It is believed that they travelled by ox-wagon. During his formative years the family moved between present day Outjo and Gobabis and finally settled in Otjiwarongo, where he first attended an actual primary school. He attended secondary school in Windhoek.
In 1941 he attended the University of Stellenbosch, South Africa on a bursary. After obtaining a BSc in engineering at the University of Stellenbosch, he was persuaded by the head of the applied mathematics department to change to an MSc in applied mathematics, which he completed in 1945. In 1946 he was appointed junior lecturer in the department of applied mathematics.
He went to work at the CSIR in Pretoria in 1947 under the supervision of . He was awarded a bursary by the CSIR to study in Britain.
Between 1947 and 1949, he did a PhD in theoretical solid state physics at the University of Bristol under Nevill Francis Mott. During his time in Bristol he befriended several people who went on to become noted physicists including C. F. Powell, Arthur Tyndall and Doris Kuhlmann-Wilsdorf. In late 1949, he returned to the CSIR.
Career in research
It was in Bristol in the period 1947 to 1949 that he started working on intercrystalline boundaries, together with Charles Frank. Eventually their research led them to study epitaxy, and in 1949 they presented the fruits of their research in a series of scientific papers. The result was the Frank–Van der Merwe crystal growth model which carries both their names.
From 1953 to 1964 he served as senior lecturer and Associate Professor in the physics department at the University of Pretoria. He completed his MSc in Mathematics from the University of Pretoria in 1956. During this period he again worked with a colleague from Bristol, Frank Nabarro who was then head of Physics at the University of the Witwatersrand, South Africa.
In 1961 he took a sabbatical to the University of Virginia which led to a refinement of his initial model of thickening two-dimensional interfaces in 1963.
The theory of epitaxy was a major focus of his career and he published many seminal papers, which resulted in him becoming known as the "Father of Epitaxy". With the advance of the semiconductor industry from the 1960s onward, epitaxy became extremely important as it depends on the growth of perfect single crystals for the manufacturing of transistors and IC circuits. An essential role in understanding how to grow such perfect crystals was provided by his theory.
Van der Merwe's model of atomic forces paved the way for successful modelling of important physical phenomena in solids at the atomic scale. He personally regarded his solution to a differential equation in his PhD thesis as one of his biggest achievements. This was basically a soliton differential equation with an ingenious solution, the first ever analytical solution to a soliton problem. Solitons in solid state and other branches of physics became important for advanced applications in communication technology.
In 1965, he was invited by an ex-CSIR colleague, Ernst Marais, to the University of Port Elizabeth where he was appointed head of the applied mathematics department. During this period Van der Merwe was invited to present plenary talks at many international conferences, during which he made enduring friendships with several surface scientists including Ernst G. Bauer of the Technical University of Clausthal-Zellerfeld and Ralf Vanselow of the University of Wisconsin, Milwaukee.
In 1969 he moved to UNISA where he became Professor of applied mathematics. In 1970 he spent a seven-month sabbatical at the University of Virginia where he collaborated with William A. Jesser. Almost 30 years later, in 1999 he co-authored a paper with Jesser.