Neda Lotfizadeh’s favorite memory of graduate school was when she took her first nanotube data. She’d worked on different projects that hadn’t been successful due to the low quality of the material available. This day, however, was different. She measured a high-quality carbon nanotube. “I could see each electron entering the nanotube, and I was over the moon! It wasn’t that unusual because this kind of thing has been done for at least 20 years, but it was still new and exciting to me,” said Lotfizadeh. She sat in the lab for an hour, just watching electrons moving into the system one-by-one. She was so excited she called her family in Iran to share the news.
Carbon Nanotubes and the Wigner Crystal
Lotfizadeh studies the transport properties of carbon nanotubes and atomically thin materials. A rolled layer of carbon atoms bonded together in a hexagonal or honeycomb mesh forms a carbon nanotube. Shaped like a test tube and measuring 1/20th of a millionth of an inch in diameter, carbon nanotubes act like a sponge in soaking up nearby molecules, making them useful because they conduct electricity better than metals. The movement of an electron within a nanotube is called transport.
In November 2019, Lotfizadeh and Vikram Deshpande, assistant professor of physics, were featured in Physical Review Letters for studying the Wigner crystal, a crystal of electrons, in one-dimension. Deshpande and Lotfizadeh measured the energy required to add an electron to the nanotube. They created a Wigner crystal by adding electrons one-by-one to a carbon nanotube suspended between two supports and cooled to 1.5 K. By measuring the energy required to add each electron, they calculated the resulting Wigner crystal’s electronic compressibility, a parameter that characterizes the ordering of electrons in the lattice. Comparing their results to predictions, the team observed the expected decrease in compressibility as electron density increased.
Lotfizadeh first became interested in physics in middle school and studied it in high school. “I was lucky to have a fantastic physics teacher in high school. She taught us that physics is really about thinking and creativity. I love the feeling of struggling with a problem and looking for ways to solve it and the feeling of achieving something—it’s like being in a maze and finding your way out,” she said.
Academics in Iran
Acceptance to a university in Iran is extremely competitive. Students take a rigorous national entrance exam to qualify each time before applying to an undergraduate, masters, or Ph.D. program. Students are required to choose a major after receiving their scores on the national exam and aren’t allowed to change their major unless they take the exam again. Lotfizadeh did well on her exams, and her father and brother wanted her to study computer science, considered a more solid career than physics in Iran. Lotfizadeh, however, wanted to study physics, a decision her mother supported. She took astronomy, particle physics, and solid state courses. Lotfizadeh fell in love with solid state and joined a computational solid-state group while studying for her master’s degree. After acceptance to a Ph.D. program, she joined another Density Functional Theory research group but had difficulty accessing the density functional theory codes because of the sanctions imposed on Iran. Her advisor, who was a fellow postdoctoral researcher from the University of California, Santa Barbara, encouraged her to apply to a doctoral program in the U.S. With the encouragement of her family, Lotfizadeh decided to come to the University of Utah.
During her graduate studies, she was involved in both WomPa (Women in Physics and Astronomy) and the Physics & Astronomy Department’s Graduate Student Advisory Committee (GSAC), serving as a WomPa coordinator for two years and as an officer of GSAC for a similar period of time. Both groups provided Lotfizadeh with valuable support during graduate school.
When she isn’t working with carbon nanotubes, Lotfizadeh paints and jogs. “Both activities help my research,” she said. “When I’m stuck on a problem and can’t come up with an answer, I jog or start painting or drawing. Later, I go back to the problem with a fresh mind.”
She will defend her thesis this semester and is looking for a postdoc position. She hopes to continue doing research and hasn’t decided if she will stay in academia or move into industry.