Alexander A. Balandin

Last updated
Alexander A. Balandin
Alexander Balandin.jpg
NationalityAmerican
Alma mater University of Notre Dame
AwardsBrillouin Medal for investigation of phonons in graphene; [1] MRS Medal for the discovery of unique heat conduction in graphene; [2] IEEE Pioneer Award in Nanotechnology
Scientific career
Fields Nanotechnology, low-dimensional materials, phonon engineering, thermal transport, electronic noise, raman spectroscopy, brillouin spectroscopy
Institutions
Website balandingroup.ucr.edu

Alexander A. Balandin is an electrical engineer, solid-state physicist, and materials scientist best known for the experimental discovery of unique thermal properties of graphene and their theoretical explanation; studies of phonons in nanostructures and low-dimensional materials, which led to the development of the field of phonon engineering; investigation of low-frequency electronic noise in materials and devices; and demonstration of the first charge-density-wave quantum devices operating at room temperature.

Contents

Academic career

Alexander A. Balandin received his BS and MS degrees Summa Cum Laude in applied mathematics and applied physics from the Moscow Institute of Physics and Technology (MIPT), Russia. He received his second MS degree and Ph.D. degree in electrical engineering from the University of Notre Dame, U.S. After completion of his postdoctoral studies at the Department of Electrical Engineering of the University of California, Los Angeles (UCLA), he joined the University of California, Riverside (UCR) as a faculty member. He is presently a Distinguished Professor of Electrical and Computer Engineering and the University of California Presidential Chair Professor of Materials Science. He has served as the Founding Chair of the campus-wide Materials Science and Engineering (MS&E) Program and as a Director of the Nanofabrication Facility (NanoFab) at UCR. Presently, he serves as a Director of the UCR's Phonon Optimized Engineered Materials (POEM) Center. Professor Balandin is a Deputy Editor-in-Chief for Applied Physics Letters (APL).

Research

Professor Balandin's research expertise covers a wide range of nanotechnology, materials science, electronics, phononics and spintronics fields with particular focus on low-dimensional materials and devices. He conducts both experimental and theoretical research. He is recognized as a pioneer of the graphene thermal field and one of the pioneers of the phononics field. His research interests include charge density wave effects in low-dimensional materials and their device applications, electronic noise in materials and devices, Brillouin – Mandelstam and Raman spectroscopy of various materials, practical applications of graphene in thermal management and energy conversion. He is also active in the areas of emerging devices and alternative computational paradigms.

Professor Balandin was among the pioneers of the field of phononics and phonon engineering. In 1998, Balandin published an influential paper on the effects of phonon spatial confinement on thermal conductivity of nanostructures, where the term “phonon engineering” appeared for the first time in a journal publication. [3] In this work, he proposed theoretically a new physical mechanism for reduction of thermal conductivity due to the changes in the phonon group velocity and density of states induced by spatial confinement. The theoretically predicted changes in the acoustic phonon spectrum in individual nanostructures were later confirmed experimentally. [4] [5] Phonon engineering has applications in electronics, thermal management, and thermoelectric energy conversion. [6]

In 2008, Professor Balandin conducted pioneering research of thermal conductivity of graphene. [7] In order to perform the first measurement of thermal properties of graphene, Balandin invented a new optothermal experiment technique based on Raman spectroscopy. [8] He and his coworkers explained theoretically why the intrinsic thermal conductivity of graphene can be higher than that of bulk graphite, and demonstrated experimentally the evolution of heat conduction when the system dimensionality changes from 2D (graphene) to 3D (graphite). [9] [10] The Balandin optothermal technique for measuring the thermal conductivity was adopted by many laboratories worldwide, and extended, with various modifications and improvements, to a range of other 2D materials. Balandin's contributions to graphene field go beyond graphene thermal properties and thermal management applications. His research group conducted detailed studies of low-frequency electronic noise in graphene devices; [11] demonstrated graphene selective sensors, which do not rely on surface functionalization; [12] and graphene logic gates and circuits, which do not require electronic band-gap in graphene. [13]

Professor Balandin made a number of important contributions to the field of low-frequency electronic noise, also known as 1/f noise. His early work in the 1/f noise field included investigation of noise sources in GaN materials and devices, which led to a substantial reduction in the noise level in such type of devices made of wide band-gap semiconductors. [14] In 2008, he started the investigation of electronic noise in graphene and other 2D materials. The main results of his research included understanding the mechanism of the 1/f noise in graphene, which is different from that in conventional semiconductors or metals; the use of few-layer graphene to address the century-old problem of surface vs. volume noise origin; [15] understanding unusual effects of irradiation on noise in graphene, which revealed a possibility of noise reduction in graphene after irradiation. [16] He successfully used noise measurements as spectroscopy for better understanding of the specifics of electron transport in graphene and other low-dimensional (1D and 2D) materials.

Professor Balandin's work helped in the rebirth of the charge density wave (CDW) research field. The early work on CDW effects was performed with bulk samples, which have quasi-1D crystal structures of strongly-bound 1D atomic chains that are weakly bound together by van der Waals forces. The rebirth of the CDW field has been associated, from one side, with the interest in layered quasi-2D van der Waals materials and, from another side, with the realization that some of these materials reveal CDW effects at room temperature and above. Balandin group demonstrated the first CDW device operating at room temperature. [17] Balandin and co-workers used original low-frequency noise spectroscopy to monitor phase transitions in 2D CDW quantum materials, [18] demonstrated the extreme radiation hardness of CDW devices [19] [20] and proposed a number of transistor-less logic circuits implemented with CDW devices. [21] [22]

Honors and awards

Balandin received the following honors and awards:

Research Group

Dr. Balandin's Group logo Balandin group.jpg
Dr. Balandin's Group logo

Balandin group's expertise covers a broad range of topics from solid-state physics to experimental investigation of advanced materials and devices with applications in electronics and energy conversion. The synergy among different research directions is in the focus on spatial confinement-induced effects in advanced materials, phonons and strongly correlated phenomena such as charge-density waves. The main research activities include Raman and Brillouin – Mandelstam light scattering spectroscopy; nanofabrication and testing of electronic devices with 2D and 1D materials; low-frequency electronic noise spectroscopy; thermal and electrical characterization of materials.

Related Research Articles

The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by , , or and is measured in W·m−1·K−1.

<span class="mw-page-title-main">Band gap</span> Energy range in a solid where no electron states exist

In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the energy difference between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band. The resulting conduction-band electron are free to move within the crystal lattice and serve as charge carriers to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer from the valence band to the conduction band, then current can flow. Therefore, the band gap is a major factor determining the electrical conductivity of a solid. Substances having large band gaps are generally insulators, those with small band gaps are semiconductor, and conductors either have very small band gaps or none, because the valence and conduction bands overlap to form a continuous band.

<span class="mw-page-title-main">Thermoelectric materials</span> Materials whose temperature variance leads to voltage change

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<span class="mw-page-title-main">Graphene</span> Hexagonal lattice made of carbon atoms

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Phaedon Avouris is a Greek chemical physicist and materials scientist. He is an IBM Fellow and was formerly the group leader for Nanometer Scale Science and Technology at the Thomas J. Watson Research Center in Yorktown Heights, New York.

<span class="mw-page-title-main">Bismuth telluride</span> Chemical compound

Bismuth telluride is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refrigeration or portable power generation. Bi2Te3 is a topological insulator, and thus exhibits thickness-dependent physical properties.

<span class="mw-page-title-main">Tantalum(IV) sulfide</span> Chemical compound

Tantalum(IV) sulfide is an inorganic compound with the formula TaS2. It is a layered compound with three-coordinate sulfide centres and trigonal prismatic or octahedral metal centres. It is structurally similar to molybdenum disulfide MoS2, and numerous other transition metal dichalcogenides. Tantalum disulfide has three polymorphs 1T-TaS2, 2H-TaS2, and 3R-TaS2, representing trigonal, hexagonal, and rhombohedral respectively.

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A charge density wave (CDW) is an ordered quantum fluid of electrons in a linear chain compound or layered crystal. The electrons within a CDW form a standing wave pattern and sometimes collectively carry an electric current. The electrons in such a CDW, like those in a superconductor, can flow through a linear chain compound en masse, in a highly correlated fashion. Unlike a superconductor, however, the electric CDW current often flows in a jerky fashion, much like water dripping from a faucet due to its electrostatic properties. In a CDW, the combined effects of pinning and electrostatic interactions likely play critical roles in the CDW current's jerky behavior, as discussed in sections 4 & 5 below.

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<span class="mw-page-title-main">Acoustic metamaterial</span> Material designed to manipulate sound waves

An acoustic metamaterial, sonic crystal, or phononic crystal is a material designed to control, direct, and manipulate sound waves or phonons in gases, liquids, and solids. Sound wave control is accomplished through manipulating parameters such as the bulk modulus β, density ρ, and chirality. They can be engineered to either transmit, or trap and amplify sound waves at certain frequencies. In the latter case, the material is an acoustic resonator.

For typical three-dimensional metals, the temperature-dependence of the electrical resistivity ρ(T) due to the scattering of electrons by acoustic phonons changes from a high-temperature regime in which ρ ∝ T to a low-temperature regime in which ρ ∝ T5 at a characteristic temperature known as the Debye temperature. For low density electron systems, however, the Fermi surface can be substantially smaller than the size of the Brillouin zone, and only a small fraction of acoustic phonons can scatter off electrons. This results in a new characteristic temperature known as the Bloch–Grüneisen temperature that is lower than the Debye temperature. The Bloch–Grüneisen temperature is defined as 2ħvskF/kB, where ħ is the Planck constant, vs is the velocity of sound, ħkF is the Fermi momentum, and kB is the Boltzmann constant.

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<span class="mw-page-title-main">Electronic properties of graphene</span>

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<span class="mw-page-title-main">Tantalum diselenide</span> Chemical compound

Tantalum diselenide is a compound made with tantalum and selenium atoms, with chemical formula TaSe2, which belongs to the family of transition metal dichalcogenides. In contrast to molybdenum disulfide (MoS2) or rhenium disulfide (ReS2), tantalum diselenide does not occur spontaneously in nature, but it can be synthesized. Depending on the growth parameters, different types of crystal structures can be stabilized.

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References

  1. ↑ "2019 Brillouin Publication" (PDF). 2019-06-07. Retrieved 2023-04-11.
  2. ↑ "MRS Medal | Materials Research Society Awards".
  3. ↑ A. Balandin and K. L. Wang, “Significant decrease of the lattice thermal conductivity due to phonon confinement in a free-standing semiconductor quantum well,” Phys. Rev. B, vol. 58, no. 3, pp. 1544–1549, Jul. 1998.
  4. ↑ A. A. Balandin, “Phonon engineering in graphene and van der Waals materials,” MRS Bull., vol. 39, no. 9, pp. 817–823, 2014.
  5. ↑ F. Kargar, B. Debnath, J.-P. Kakko, A. Säynätjoki, H. Lipsanen, D. L. Nika, R. K. Lake, and A. A. Balandin, “Direct observation of confined acoustic phonon polarization branches in free-standing semiconductor nanowires,” Nature Commun., vol. 7, p. 13400, Nov. 2016.
  6. ↑ A. A. Balandin, “Phononics of graphene and related materials,” ACS Nano, vol. 14, pp. 5170-5178, 2020.
  7. ↑ A. A. Balandin, S. Ghosh, W. Bao, I. Calizo, D. Teweldebrhan, F. Miao, and C. N. Lau, “Superior thermal conductivity of single-layer graphene,” Nano Lett., vol. 8, no. 3, pp. 902–907, Mar. 2008.
  8. ↑ A. A. Balandin, “Thermal properties of graphene and nanostructured carbon materials,” Nat. Mater., vol. 10, no. 8, pp. 569–581, 2011.
  9. ↑ S. Ghosh, W. Bao, D. L. Nika, S. Subrina, E. P. Pokatilov, C. N. Lau, and A. A. Balandin, “Dimensional crossover of thermal transport in few-layer graphene,” Nat. Mater., vol. 9, no. 7, pp. 555–558, 2010.
  10. ↑ D. L. Nika and A. A. Balandin, “Phonons and thermal transport in graphene and graphene-based materials,” Reports Prog. Phys., vol. 80, no. 3, p. 36502, Mar. 2017.
  11. ↑ A. A. Balandin, “Low-frequency 1/f noise in graphene devices,” Nat Nano, vol. 8, no. 8, pp. 549–555, Aug. 2013.
  12. ↑ S. Rumyantsev, G. Liu, M. S. Shur, R. A. Potyrailo, and A. A. Balandin, “Selective gas sensing with a single pristine graphene transistor,” Nano Lett., vol. 12, no. 5, pp. 2294–2298, May 2012.
  13. ↑ G. Liu, S. Ahsan, A. G. Khitun, R. K. Lake, and A. A. Balandin, “Graphene-based non-Boolean logic circuits,” J. Appl. Phys., vol. 114, no. 15, p. 154310, Oct. 2013.
  14. ↑ A. Balandin, S. V. Morozov, S. Cai, R. Li, K. L. Wang, G. Wijeratne, C. R. Viswanathan, “Low flicker-noise GaN/AlGaN heterostructure field-effect transistors for microwave communications,” IEEE Trans. Microw. Theory Tech., vol. 47, no. 8, pp. 1413–1417, 1999.
  15. ↑ G. Liu, S. Rumyantsev, M. S. Shur, and A. A. Balandin, “Origin of 1/f noise in graphene multilayers: surface vs. volume,” Appl. Phys. Lett., vol. 102, no. 9, p. 93111, Mar. 2013.
  16. ↑ M. Zahid Hossain, S. Rumyantsev, M. S. Shur, and A. A. Balandin, “Reduction of 1/f noise in graphene after electron-beam irradiation,” Appl. Phys. Lett., vol. 102, no. 15, p. 153512, Apr. 2013.
  17. ↑ G. Liu, B. Debnath, T. R. Pope, T. T. Salguero, R. K. Lake, and A. A. Balandin, “A charge-density-wave oscillator based on an integrated tantalum disulfide–boron nitride–graphene device operating at room temperature,” Nature Nano, vol. 11, no. 10, pp. 845–850, Oct. 2016.
  18. ↑ G. Liu, S. Rumyantsev, M. A. Bloodgood, T. T. Salguero, and A. A. Balandin, "Low-frequency current fluctuations and sliding of the charge density waves in two-dimensional materials," Nano Letters, vol. 18, no. 6, pp. 3630–3636, 2018.
  19. ↑ G. Liu, E. X. Zhang, C. Liang, M. Bloodgood, T. Salguero, D. Fleetwood, A. A. Balandin, “Total-ionizing-dose effects on threshold switching in 1T-TaS2 charge density wave devices,” IEEE Electron Device Lett., vol. 38, no. 12, pp. 1724–1727, Dec. 2017.
  20. ↑ A. K. Geremew, F. Kargar, E. X. Zhang, S. E. Zhao, E. Aytan, M. A. Bloodgood, T. T. Salguero, S. Rumyantsev, A. Fedoseyev, D. M. Fleetwood and A. A. Balandin, “Proton-irradiation-immune electronics implemented with two-dimensional charge-density-wave devices,” Nanoscale, vol. 11, no. 17, pp. 8380–8386, 2019.
  21. ↑ A. Khitun, G. Liu, and A. A. Balandin, “Two-dimensional oscillatory neural network based on room-temperature charge-density-wave devices,” IEEE Trans. Nanotechnol., vol. 16, no. 5, pp. 860–867, Sep. 2017.
  22. ↑ A. G. Khitun, A. K. Geremew, and A. A. Balandin, “Transistor-less logic circuits implemented with 2-D charge density wave devices,” IEEE Electron Device Lett., vol. 39, no. 9, pp. 1449–1452, 2018.
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