Researchers at the University of Houston have discovered that high-purity boron arsenide crystals conduct heat better than diamond, reaching over 2,100 watts per meter per Kelvin at room temperature. This breakthrough challenges existing theories and promises advancements in electronics. The findings were published in Materials Today.
Scientists have long viewed diamond as the ultimate isotropic thermal conductor, but a new study led by the University of Houston reveals that boron arsenide (BAs) can surpass it under ideal conditions. The research, conducted by the Texas Center for Superconductivity at the University of Houston in collaboration with the University of California, Santa Barbara, and Boston College, demonstrates that exceptionally pure BAs crystals achieve thermal conductivity above 2,100 W/mK at room temperature—potentially exceeding diamond's performance.
The journey began over a decade ago. In 2013, physicist David Broido from Boston College predicted that BAs could match or outperform diamond in heat conduction. However, 2017 theoretical models incorporating four-phonon scattering lowered expectations to around 1,360 W/mK, leading many to dismiss the material's potential. Early experiments yielded only about 1,300 W/mK due to impurities in the crystals.
Zhifeng Ren, professor of physics at the University of Houston and the study's corresponding author, suspected that defects, not inherent limitations, were the issue. By refining raw arsenic and improving synthesis methods, his team produced cleaner crystals that shattered previous records. "We trust our measurement; our data is correct and that means the theory needs correction," Ren said. "I'm not saying the theory is wrong, but an adjustment needs to be made to be consistent with the experimental data."
This discovery highlights the critical role of material purity in thermal performance and could transform semiconductor technology. Unlike diamond, which requires extreme conditions to produce, BAs offers easier, more cost-effective manufacturing while combining superior heat dissipation with strong semiconductor properties, including high carrier mobility and a wide band gap. "This new material, it's so wonderful," Ren added. "It has the best properties of a good semiconductor, and a good thermal conductor—all sorts of good properties in one material. That has never happened in other semiconducting materials."
The work is part of a $2.8 million National Science Foundation project led by Bolin Liao at UC Santa Barbara, involving the University of Houston, the University of Notre Dame, and UC Irvine, with support from industrial partner Qorvo. Researchers plan to further refine BAs to push boundaries even more. As Ren noted, "You shouldn't let a theory prevent you from discovering something even bigger, and this exactly happened in this work." The study challenges scientists to revisit models and explore underestimated materials for applications in smartphones, high-power electronics, and data centers.