Project Grant 2302879

CDS & E: COUPLED ELECTRO-THERMAL TRANSPORT IN TWO-DIMENSIONAL MATERIALS AND HETEROSTRUCTURES -THIS PROJECT IS FUNDED THROUGH THE COMPUTATIONAL AND DATA-ENABLED SCIENCE AND ENGINEERING PROGRAM BY CONTRIBUTIONS FROM CONDENSED MATTER AND MATERIALS THEORY PROGRAM OF THE DIVISION OF MATERIALS RESEARCH AND THE THERMAL TRANSPORT PROCESSES PROGRAM OF THE DIVISION OF CHEMICAL, BIOENGINEERING, ENVIRONMENTAL, AND TRANSPORT SYSTEMS. NONTECHNICAL SUMMARY THIS AWARD SUPPORTS COMPUTATIONAL RESEARCH FOR THE DEVELOPMENT AND APPLICATIONS OF A SIMULATION TOOL TO MODEL THE TRANSPORT OF CHARGE AND HEAT CARRIERS IN TWO-DIMENSIONAL (2D) MATERIALS. 2D MATERIALS ARE A BROAD COHORT OF NOVEL MATERIALS IN THE FORM OF ATOMICALLY THIN SHEETS HAVING A THICKNESS OF ONLY ONE OR A FEW ATOMS. OWING TO THEIR ULTIMATE THINNESS, SUCH MATERIALS HOLD TREMENDOUS PROMISE AS A PLATFORM FOR FUTURE ENERGY-EFFICIENT NANOELECTRONIC AND ENERGY DEVICES, WHICH MAY ENABLE EXTREMELY DENSE INTEGRATED CIRCUITS, AND WEARABLE AND MULTIFUNCTIONAL ELECTRONICS. ELECTRONIC AND THERMAL PROPERTIES OF MATERIALS ARE NOT ONLY MUTUALLY COUPLED BUT STRONGLY INTERDEPENDENT: ELECTRICAL RESISTANCE INCREASES DRASTICALLY WITH TEMPERATURE, WHICH, IN TURN, INCREASES HEAT DISSIPATION, CREATING HOT SPOTS THAT WASTE ENERGY AND LIMIT PERFORMANCE. THIS IS PARTICULARLY PRONOUNCED IN 2D MATERIALS, WHOSE ATOMIC THINNESS AND RELATIVELY WEAK COUPLING TO THE ENVIRONMENT MAY PRESENT A BOTTLENECK TO HEAT REMOVAL. IN THIS PROJECT, THE PI WILL DEVELOP AND RELEASE A CODE THAT TREATS THE DYNAMICS OF CHARGE AND HEAT CARRIERS CONCURRENTLY IN VARIOUS 2D MATERIALS OF SCIENTIFIC AND TECHNOLOGICAL RELEVANCE. THE CODE TO BE DEVELOPED WILL BE DISSEMINATED FREELY TO THE COMMUNITY, ALONG WITH MAINTAINING A DEDICATED WEBSITE FOR FORUMS AND DOCUMENTATION. THIS AWARD ALSO SUPPORTS THE PI'S EDUCATIONAL AND OUTREACH ACTIVITIES, WHICH INCLUDE TRAINING AND MENTORING THE NEXT GENERATION OF COMPUTATIONAL MATERIALS SCIENTISTS AND INTRODUCING COMPUTATIONAL SCIENCE TO STUDENTS ACROSS LEVELS, BY REDESIGNING CORE MATERIALS COURSES, RECRUITING UNDERREPRESENTED STUDENTS IN SCIENCE, MATH, AND ENGINEERING DISCIPLINES, AND CREATING FREE ONLINE EDUCATIONAL MODULES TO TEACH UNDERGRADUATE STUDENTS HIGH-PERFORMANCE AND PARALLEL COMPUTING. TECHNICAL SUMMARY THIS AWARD SUPPORTS COMPUTATIONAL RESEARCH FOR THE DEVELOPMENT AND APPLICATIONS OF A SIMULATION TOOL TO SOLVE THE COUPLED BOLTZMANN TRANSPORT EQUATIONS FOR ELECTRONS AND PHONONS IN TWO-DIMENSIONAL (2D) MATERIALS. SIMULATING THERMAL DISSIPATION INSIDE 2D NANOSTRUCTURES REQUIRES A TWO-WAY COUPLED TREATMENT OF ELECTRONS AND HEAT, THE LATTER BEING TRANSPORTED BY PHONONS. COMPUTING ELECTRON-PHONON COUPLING FROM FIRST PRINCIPLES AND SOLVING THE ELECTRON AND PHONON BOLTZMANN TRANSPORT EQUATIONS USING AB INITIO INPUTS HAS NOW REACHED FULL MATURITY. HOWEVER, THERE IS A CRITICAL NEED FOR A PLATFORM THAT WILL ENABLE STUDYING NON-ISOTHERMAL TRANSPORT, WHERE ELECTRON AND PHONON POPULATIONS ARE SIMULATED CONCURRENTLY SO THAT PHONONS GENERATED BY ELECTRON-PHONON COUPLING ARE TRACKED AND THEIR DISTRIBUTION/TEMPERATURE FED BACK INTO ELECTRON TRANSPORT AND VICE VERSA. TO ADDRESS THIS NEED, THE PI WILL DEVELOP AND RELEASE A CODE, CALLED CELPHONBTE2D, FOR TWO-WAY COUPLED ELECTRON-PHONON BOLTZMANN TRANSPORT SIMULATION OF 2D MATERIALS AND HETEROSTRUCTURES. THE CODE WILL BUILD ON FIRST-PRINCIPLES DATA TO ENABLE PREDICTIVE SIMULATION FOR REALISTIC APPLICATIONS. THE CODE TO BE DEVELOPED WILL BE DISSEMINATED VIA THE NANOHUB, WHICH WILL HOST SOURCE CODE AND TRACK USAGE, ALONG WITH A DEDICATED WEBSITE FOR FORUMS AND DOCUMENTATION. THIS AWARD ALSO SUPPORTS THE PI'S EDUCATIONAL AND OUTREACH ACTIVITIES, WHICH INCLUDE TRAINING AND MENTORING THE NEXT GENERATION OF COMPUTATIONAL MATERIALS SCIENTISTS AND INTRODUCING COMPUTATIONAL SCIENCE TO STUDENTS ACROSS LEVELS, BY REDESIGNING CORE MATERIALS COURSES, RECRUITING UNDERREPRESENTED STUDENTS IN STEM DISCIPLINES, AND CREATING FREE ONLINE EDUCATIONAL MODULES TO TEACH UNDERGRADUATE STUDENTS HIGH-PERFORMANCE AND PARALLEL COMPUTING. THIS AWARD REFLECTS NSF'S STATUTORY MISSION AND HAS BEEN DEEMED WORTHY OF SUPPORT THROUGH EVALUATION USING THE FOUNDATION'S INTELLECTUAL MERIT AND BROADER IMPACTS REVIEW CRITERIA.