My research expertise is in general area of condensed matter and materials physics. I am particularly interested in understanding heat transfer in semiconducting materials where phonons (i.e., quanta of collective excitations in a lattice) are dominant heat carriers. Understanding phonon transport is important for designing quantum materials and devices with desirable thermal properties. In the past, I have made contributions to two fundamental problems in this area as described below.

Heat management in electronic devices:

Affiliations: JILA (joint research institute of CU Boulder and NIST), the Kapteyn-Murnane Group (pioneers in ultrafast optical and x-ray science) and the NSF Science and Technology Center on Real-Time Functional Imaging (STROBE), 2018-2020

Overheating in solid-state electronics such as laptops and cell phones often decreases their efficiencies and lifetimes. In my postdoctoral research, our goal was to understand the fundamental mechanisms underlying overheating in materials using atomistic simulations and theories supported by extreme ultraviolet experiments. As a major outcome of this research, we have shown that a material overheats less (or cools down faster) when heat sources are tightly packed at nanometer scales. We have found that this is due to the directional behavior of phonons (atomic vibrations). These new concepts lay the foundation for future quantum engineers to design thermally efficient devices as modern transistors shrink in size to as small as 5 nanometers. This research has been published in the  Proceedings of the National Academy of Sciences (PNAS). Our work was among top 5% of the publications ever tracked by Altmetric.  Our work was also covered in nine news agencies including Phys.org,  Scienmag, and East Bay Times (see here for the full list).

Thermoelectric materials:

Affiliation: CU Boulder Phononics Laboratory (pioneers in phononic materials), 2013 to 2018

During my PhD, I studied phonon transport in nanophononic metamaterials (NPMs) using large-scale atomistic models. An NPM serves as a thermoelectric material to efficiently convert heat into electricity. The concept of NPM was originally proposed by our group in a 2014 Physical Review Letter article and received wide media attention including a focus article in Physics. My thesis built upon this idea and took the concept to a totally new level by developing advanced modeling techniques to unveil the novel physics behind NPM. My research has resulted in several high-impact publications and has been recognized by prestigious awards. A major contribution of my thesis was the fundamental and record-breaking results published in a 2018 Physical Review B article. This article is important for thermoelectric science and technology since it presents a silicon-based thermoelectric material with significantly higher performance than the current state-of-the-art materials. Following this article, my adviser was awarded a $2.5 million grant from the Advanced Research Projects Agency-Energy (ARPA‑E) to manufacture high-performance NPM devices. In 2019, our review article on the NPM research was featured on the cover of Advanced Functional Materials journal.

For more detailed information about my research, you can download my CV.

For the full list of my publications, you can visit my Google Scholar profile. 

Book chapter

• M. I. Hussein and H. Honarvar, "Resonant thermal transport in nanophononic metamaterials," in: Andreoni, W. and Yip, S. (eds) Handbook of Materials Modeling, Springer, Cham, 2018.

Journal articles

• H. Honarvar, J. L. Knobloch, T. D. Frazer, B. Abad, B. McBennett, M. I. Hussein, H. C. Kapteyn, M. M. Murnane, J. N. Hernandez-Charpak,  "Directional thermal channeling: A phenomenon triggered by tight packing of heat sources," Proceedings of the National Academy of Sciences, 118 (40), 2021.

• H. Honarvar and M. I. Hussein, "Two orders of magnitude reduction in silicon membrane thermal conductivity by resonance hybridizations," Physical Review B, 97, 195413, 2018.

• My postdoctroal research resulted in a fundamental disovery in heat transfer in quantum materials and received wide media attention, JILA, CU Boulder and NIST, 2021.

• The fundamental and record-breaking results of my PhD research led to an ARPA‑E grant awarded to my adviser to manufacture high-performance thermoelectric devices,  CU Boulder, 2018.

• Awarded the Teets Family Endowed Doctoral Fellowship in recognition of an outstanding graduate student carrying out research related to micro/nano systems in engineering and life sciences, CU Boulder, 2016.