Preface for the Women's perspectives in 2D materials focus issue

In the 15 years since graphene was first isolated the world has changed considerably. In science labs alone we have detected gravitational waves, designed techniques to edit genes within organisms and identified the Higgs boson. What hasn't changed much is the representation of women or minorities in physics and materials science. When graphene was first isolated in 2004, women made up just 10% of physics professors in the United States and only 4% in the United Kingdom [1–3]. In the years since the representation of women studying physics at high school, earning bachelor's degrees in physics and being promoted to professor has barely changed. Despite global efforts toward gender equality in science, a recent study of over 10 million scientific papers found that we are 258 years away from gender balance of authors of physics publications [4]. When Forbes announced their 100 Most Innovative Leaders in 2019, the list only included one woman [5]. This focus issue concentrates on women researchers working with 2D materials; celebrating their contributions to our understanding and application of these fascinating structures.

WHY DOES IT MATTER?

Diversity within the scientific community is not only an issue of social justice, but important for the quality of the science we do and the inclusiveness of the system we create. More diverse teams are better at problem solving, are more creative and more innovative. In 2018 the British physicist Professor Dame Jocelyn Bell-Burnell was awarded the Breakthrough Prize for her 1967 discovery of pulsars [6]. Recognising the importance of diversity within science, Burnell donated the entirety of her $3 million prize into the postgraduate research of people from underrepresented groups. From energy generation and storage to transport and drug delivery, 2D materials will undoubtedly find applications in so many areas of our lives, it is essential that the people developing them represent the diverse communities they are going to serve.

WHY ARE WOMEN UNDERREPRESENTED?

The origins of women's underrepresentation in materials science research are complex; the underrepresentation of girls in physics and advanced maths at high school impacts their representation in undergraduate physics, engineering and materials science courses, and their experiences at undergraduate level affects the number of women graduate students, lecturers and professors. Indeed, most equality efforts focus solely on increasing the percentage of girls who would consider studying these courses at high-school university. But filling our lecture theatres and laboratories with talented young women will not solve science's gender gap: the scientific community has to be ready to welcome them and, most importantly, treat them as equals.

The power imbalances, in-built bias, unequal workloads and uncertain career paths make academia intimidating for anyone to enter, but it is particularly difficult if you are from a group that's typically underrepresented in science. Research funding, peer-reviewed publications and student feedback on teaching, all crucial in an academics promotion to professor, are known to favour white men [7–9]. Men are not only more likely to be asked to review papers and serve on Editorial Boards, but more likely to have their papers accepted and cited [10]. Women are more likely to take on academic service roles, which takes time away from their research and is less valued in promotion [11]. Recent studies have demonstrated that sexual harassment and bullying are rife within physics and engineering programmes, increasing women's likelihood to leave academia.

WHAT CAN WE DO?

The gender balance of physics classrooms has been extensively investigated by the education team at the Institute of Physics [12]. For over twenty years they have collected data, trained teachers and investigated the reasons why girls do not choose to study physics. They have identified that girls do not opt out of physics because of talent, ability or interest, but because of stereotyping, poor career advice and lack of skills-specialist science teachers.

In the United Kingdom, the Institute of Physics' Juno award and Advance HE's Athena SWAN charter are award programs that recognise institutional commitment to advancing gender equality. Both encourage organisations to collect quantitative and qualitative data, have fair appointment and promotion processes, transparent workload allocations, opportunities to work flexibly and expectations of professional conduct that are embedded into the workplace culture. In short; Athena SWAN and Juno make academic departments better for everyone studying and working inside them.

To retain scientists from underrepresented groups is as important as it is to recruit them, and there are efforts we can all take to make our labs more welcoming;

• Be an active ally—ask questions about people's experiences, and be prepared to listen.
• Find out what would help scientists from underrepresented groups and seek out ways to make that happen.
• Provide proper parental leave, including support for people before and after maternity leave, and be prepared to freeze grants and proposals if people need time for their families, physical or mental health.
• Make your workload allocation transparent, do not have meetings late and do not set important deadlines in school holidays.
• Celebrate all of your faculty members—watch out for fellowships, award schemes and speaking opportunities and nominate women.
• Include women scientists when writing your course materials, lectures and textbooks—even write their biographies on Wikipedia.
• Check your seminar series and conference programmes—invite scientists from underrepresented groups to speak, chair and lead. If you need inspiration, you're in the right place—this focus issue features the work of women leaders from all over the world. For more, check out 500 Women Scientists' platform Request A Woman Scientist [13].
• Seek out the work of women scholars and, where appropriate, cite them.

This focus issue demonstrates that not only has our understanding and application of 2D materials benefited from a variety of scientific disciplines; but that the diversity of people doing the research itself is equally as advantageous in a field that is driven by innovation, creativity and scientific breakthroughs.