About

Professor Alexander A. Balandin is a Distinguished Professor in the Department of Materials Science and Engineering at UCLA. He is also affiliated with the California NanoSystems Institute. His research focuses on materials science and engineering, with an emphasis on nano-scale materials and their applications. As the principal investigator of the Balandin Group, he leads research efforts in advanced materials, nanotechnology, and their integration into various technological applications. His work contributes to the development of innovative materials with unique properties, advancing the fields of nanoelectronics, photonics, and thermal management.

Research topics

• Materials science
• Physics
• Nanotechnology
• Condensed matter physics
• Computer Science
• Quantum mechanics
• Optoelectronics
• Chemistry
• Optics
• Engineering physics
• Composite material
• Electrical engineering

Selected publications

• Radio-Frequency-Driven Reshaping of the Mesoscale Charge-Density-Wave Landscape in 1T-TaS2 Thin-Film Devices

  ArXiv.org · 2026-04-01

  articleOpen accessSenior author

  Radio-frequency excitation directly reshapes the mesoscale charge-density-wave landscape in quasi-two-dimensional 1T-TaS2 thin films. Under combined RF and DC bias, the hysteretic current-voltage characteristics associated with the nearly commensurate-incommensurate transition are strongly altered, displaying RF-driven collapse, branching, and multiple step-like features that depend on frequency and drive amplitude. In-situ Raman measurements show enhanced intensity and linewidth narrowing of low-frequency CDW phonon modes, consistent with reduced dephasing and increased coherence of the periodic lattice distortion under RF drive. This behavior is captured by combining an overdamped time-dependent Ginzburg-Landau description of the commensurate CDW with a morphology-informed percolative resistor-capacitor transport model. The simulations indicate that oscillatory driving anneals frustrated domain configurations, reduces domain-wall density, and reorganizes the discommensuration network, while the transport model reproduces the resulting hysteresis, avalanche-like pathways, and RF-induced conductance steps. RF driving therefore provides an effective route for controlling collective electron-phonon order and accessing metastable transport states in 1T-TaS2, with implications for reconfigurable RF electronics, memory, and unconventional computing based on correlated materials.

  PublisherOA PDF

• Phonon Signatures of Near-Room-Temperature Phase Transition in Quasi-One-Dimensional Bi4I4 Topological van der Waals Material

  arXiv (Cornell University) · 2026-03-31

  articleOpen accessSenior author

  The quasi-one-dimensional material Bi4I4 hosts two crystallographically similar polymorphs that realize distinct topological insulating phases separated by a first-order structural transition near room temperature. This transition occurs without a change in space group, arising instead from a subtle rearrangement of chain stacking registry. Polarization-resolved Raman spectroscopy directly resolves this structural-topological phase transition through abrupt, hysteretic modifications of the phonon spectrum. Angle-dependent measurements establish the symmetry of the dominant Raman-active modes and require a complex Raman tensor formalism to account for absorption-induced phase effects. Across the transition, selected phonon modes exhibit discontinuous, reversible shifts in frequency, linewidth, and relative intensity despite the absence of a space-group change. Density functional theory calculations reproduce the direction of the observed phonon renormalizations and confirm their sensitivity to stacking-dependent force constants. These results demonstrate that polarization-resolved Raman spectroscopy can detect subtle stacking-driven structural rearrangements that underlie topological band character, even when global crystallographic symmetry remains unchanged. The obtained results provide valuable insights into the interplay among lattice dynamics, structural distortions, and topological properties in this class of low-dimensional materials, with strong potential for unique functionalities.

  PublisherOA PDF

• Electrically and Magnetically Tunable Charge-Density-Wave Transport in Quasi-2D h-BN/1T-TaS2 Thin-Film Heterostructures

  arXiv (Cornell University) · 2026-03-29

  articleOpen accessSenior author

  Controlling collective electronic phases in low-dimensional materials is a central challenge for developing technologies based on charge-density waves. Here, we report that perpendicular electric and magnetic fields can be used to tune charge-density-wave transport in the quasi-two-dimensional material 1T-TaS2. Using h-BN-encapsulated thin-film heterostructures with both top-gate and bottom-gate configurations, we find that electrical gating produces a non-monotonic shift in the depinning threshold, a behavior distinct from that of quasi-one-dimensional charge-density-wave systems. We further show that a perpendicular magnetic field increases the threshold voltage for domain depinning and can drive the nearly commensurate-to-incommensurate charge-density-wave phase transition, demonstrating magnetic control over a two-dimensional electron-lattice condensate. The obtained results shed light on mechanisms governing charge-density-wave domain dynamics and reveal combined electrical and magnetic-field control as a strategy for engineering low-power-dissipation devices and electronics for extreme environments.

  PublisherOA PDF

• Electrically and Magnetically Tunable Charge–Density–Wave Transport in Quasi‐2D <i>h</i> ‐BN/1 <i>T</i> ‐TaS ₂ Field Effect Devices

  Advanced Electronic Materials · 2026-05-06

  articleOpen accessSenior author

  ABSTRACT Controlling collective electronic phases in low‐dimensional materials is a central challenge for developing technologies based on charge‐density‐waves. Here, we report that perpendicular electric and magnetic fields can be utilized to tune the charge‐density‐wave transport in the quasi‐two‐dimensional material 1 T‐polytype tantalum disulfide. Using hexagonal boron nitride encapsulated thin‐film heterostructures with both top‐gate and bottom‐gate configurations, we find that electrical gating produces a non‐monotonic shift in the depinning threshold—behavior distinct from quasi‐one‐dimensional charge‐density‐wave systems. We further show that a perpendicular magnetic field increases the threshold voltage for domain depinning and can drive the incommensurate‐to‐nearly commensurate charge‐density‐wave phase transition, demonstrating magnetic control over a two‐dimensional electron–lattice condensate. The obtained results shed light on mechanisms governing charge‐density‐wave domain dynamics and reveal combined electrical and magnetic‐field control as a strategy for engineering low‐power‐dissipation devices and electronics for extreme environments.

  PublisherDOI

• Angle-Resolved Cryogenic Brillouin-Mandelstam Spectroscopy of Surface and Bulk Acoustic Phonons in Diamond

  arXiv (Cornell University) · 2026-05-09

  preprintOpen accessSenior author

  We used angle-resolved Brillouin-Mandelstam light-scattering spectroscopy to monitor surface and bulk acoustic phonons in diamond along the &lt;100&gt; and &lt;110&gt; crystallographic directions across a temperature range from 10 K to 300 K. The frequencies and phase velocities were measured for three types of surface acoustic phonons: Rayleigh waves, shear horizontal waves, and high-frequency pseudo-longitudinal waves. All surface acoustic phonons exhibit weak temperature dependence, with the largest observed change of 1.6% across the examined temperature range. The frequencies of all three types of surface acoustic phonons agree with the theoretical values within the experimental uncertainty. Cryogenic surface-acoustic-phonon data are important for diamond-based quantum sensors, surface acoustic wave devices, and other electronic technologies. Knowledge of surface acoustic phonons can also be used for developing accurate models for thermal transport between interfaces.

  PublisherDOI

• Radio-Frequency-Driven Reshaping of the Mesoscale Charge-Density-Wave Landscape in 1T-TaS2 Thin-Film Devices

  arXiv (Cornell University) · 2026-04-01

  preprintOpen accessSenior author

  Radio-frequency excitation directly reshapes the mesoscale charge-density-wave landscape in quasi-two-dimensional 1T-TaS2 thin films. Under combined RF and DC bias, the hysteretic current-voltage characteristics associated with the nearly commensurate-incommensurate transition are strongly altered, displaying RF-driven collapse, branching, and multiple step-like features that depend on frequency and drive amplitude. In-situ Raman measurements show enhanced intensity and linewidth narrowing of low-frequency CDW phonon modes, consistent with reduced dephasing and increased coherence of the periodic lattice distortion under RF drive. This behavior is captured by combining an overdamped time-dependent Ginzburg-Landau description of the commensurate CDW with a morphology-informed percolative resistor-capacitor transport model. The simulations indicate that oscillatory driving anneals frustrated domain configurations, reduces domain-wall density, and reorganizes the discommensuration network, while the transport model reproduces the resulting hysteresis, avalanche-like pathways, and RF-induced conductance steps. RF driving therefore provides an effective route for controlling collective electron-phonon order and accessing metastable transport states in 1T-TaS2, with implications for reconfigurable RF electronics, memory, and unconventional computing based on correlated materials.

  PublisherDOI

• Phonon Signatures of Near-Room-Temperature Phase Transition in Quasi-One-Dimensional Bi4I4 Topological van der Waals Material

  arXiv (Cornell University) · 2026-03-31

  preprintOpen accessSenior author

  The quasi-one-dimensional material Bi4I4 hosts two crystallographically similar polymorphs that realize distinct topological insulating phases separated by a first-order structural transition near room temperature. This transition occurs without a change in space group, arising instead from a subtle rearrangement of chain stacking registry. Polarization-resolved Raman spectroscopy directly resolves this structural-topological phase transition through abrupt, hysteretic modifications of the phonon spectrum. Angle-dependent measurements establish the symmetry of the dominant Raman-active modes and require a complex Raman tensor formalism to account for absorption-induced phase effects. Across the transition, selected phonon modes exhibit discontinuous, reversible shifts in frequency, linewidth, and relative intensity despite the absence of a space-group change. Density functional theory calculations reproduce the direction of the observed phonon renormalizations and confirm their sensitivity to stacking-dependent force constants. These results demonstrate that polarization-resolved Raman spectroscopy can detect subtle stacking-driven structural rearrangements that underlie topological band character, even when global crystallographic symmetry remains unchanged. The obtained results provide valuable insights into the interplay among lattice dynamics, structural distortions, and topological properties in this class of low-dimensional materials, with strong potential for unique functionalities.

  PublisherDOI

• Angle-Resolved Cryogenic Brillouin-Mandelstam Spectroscopy of Surface and Bulk Acoustic Phonons in Diamond

  ArXiv.org · 2026-05-09

  articleOpen accessSenior author

  We used angle-resolved Brillouin-Mandelstam light-scattering spectroscopy to monitor surface and bulk acoustic phonons in diamond along the <100> and <110> crystallographic directions across a temperature range from 10 K to 300 K. The frequencies and phase velocities were measured for three types of surface acoustic phonons: Rayleigh waves, shear horizontal waves, and high-frequency pseudo-longitudinal waves. All surface acoustic phonons exhibit weak temperature dependence, with the largest observed change of 1.6% across the examined temperature range. The frequencies of all three types of surface acoustic phonons agree with the theoretical values within the experimental uncertainty. Cryogenic surface-acoustic-phonon data are important for diamond-based quantum sensors, surface acoustic wave devices, and other electronic technologies. Knowledge of surface acoustic phonons can also be used for developing accurate models for thermal transport between interfaces.

  PublisherOA PDF

• A quieter state of charge and ultra-low-noise of the collective current in quasi-1D charge-density-wave nanowires

  Nature Communications · 2025-12-31

  articleOpen accessSenior author

  Abstract Electronic flicker noise limits phase stability in communication systems, reduces the sensitivity and selectivity of sensors, and degrades coherence in quantum devices. There is a strong need for unconventional materials and strategies for achieving ultra-low-noise performance in nanoscale and quantum electronics. Here, we demonstrate that in nanowires of the quasi-one-dimensional, fully gapped charge-density-wave material (TaSe 4 ) 2 I, low-frequency electronic noise is suppressed below the limit of thermalized charge carriers in passive resistors. When the current is dominated by the sliding Frohlich condensate, the normalized noise spectral density, $${S}_{I}/{I}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>S</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:msup> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> , decreases linearly with current, $$I$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>I</mml:mi> </mml:math> — a striking departure from the constant value of $${S}_{I}/{I}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>S</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:msup> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> , observed in conventional conductors. No residual minimum noise level is reached for the current of the electron-lattice condensate in (TaSe 4 ) 2 I nanowires. Repeating the measurements for another charge-density wave conductor, NbS 3 -II, we found a similar reduction below the normal electron limit at room temperature. Our findings signal intrinsically lower current fluctuations within a correlated electron transport regime.

  PublisherDOI

• Anomalous spin-lattice coupling in a 2D antiferromagnetic semiconductor revealed by surface acoustic Rayleigh waves

  ArXiv.org · 2025-11-26

  preprintOpen accessSenior author

  Magnetic order in van der Waals magnets can strongly influence their lattice dynamics, yet how this interaction manifests across different phonon length scales remains unclear. Optical phonons probe bond-scale exchange modulation and short-range spin correlations, whereas long-wavelength acoustic modes couple to uniform strain fields and are sensitive to the renormalization of the macroscopic elastic tensor associated with long-range magnetic order. Experimentally accessing these low-energy acoustic excitations in low-dimensional crystals is challenging due to their low energies and the small lateral dimensions of exfoliated samples. Here, we employ angle-resolved Brillouin-Mandelstam scattering spectroscopy to investigate the surface acoustic phonon spectrum of exfoliated NiPS3 thin films across their antiferromagnetic transition temperature. Our results show a single Rayleigh surface mode whose phase velocity exhibits a pronounced 5.5% softening upon cooling through the Neel temperature. This anomaly reflects a giant magnetoelastic renormalization of the long-wavelength elastic constants triggered by the onset of zigzag antiferromagnetic order. First-principles calculations of the full elastic tensor, combined with continuum finite-element modelling of the NiPS3/SiO2/Si heterostructure, reproduce both the Rayleigh-wave dispersion and its magnetic-order-induced shift. The obtained results reveal how microscopic exchange interactions shape macroscopic mechanical properties in two-dimensional antiferromagnetic semiconductors, providing a basis for lattice-controlled magnetism and magnetically tunable phononic, magnonic, and strain-mediated spintronic device concepts.

  PublisherOA PDFDOI

Recent grants

• DMREF: Collaborative research: Data driven discovery of synthesis pathways and distinguishing electronic phenomena of 1D van der Waals bonded solids

  NSF · $1.1M · 2019–2024

• NEB: Charge-Density-Wave Computational Fabric: New State Variables and Alternative Material Implementation

  NSF · $1.3M · 2011–2016

• CDS&E/Collaborative Research: Genetic Algorithm Driven Hybrid Computational/Experimental Engineering of Defects in Designer Materials

  NSF · $168k · 2014–2018

• MRI: Development of a Cryogenic Integrated Micro-Raman-Brillouin-Mandelstam Spectrometer

  NSF · $519k · 2020–2024

• Collaborative Research: EAGER: Enhancing Pyroelectric Effects in Nanostructured Materials for High-Efficiency Energy Conversion

  NSF · $75k · 2015–2017

Frequent coauthors

• Sergey Rumyantsev

  Institute of High Pressure Physics

  182 shared

• Fariborz Kargar

  172 shared

• Denis L. Nika

  Moldova State University

  87 shared

• Guanxiong Liu

  Harbin Institute of Technology

  76 shared

• Roger K. Lake

  University of California, Riverside

  72 shared

• Tina T. Salguero

  University of Georgia

  60 shared

• Desalegne Teweldebrhan

  University of California, Riverside

  56 shared

• Adane K. Geremew

  Institute of High Pressure Physics

  54 shared

Labs

• Balandin GroupPI

Education

• Ph.D., Electrical Engineering

  University of California, Los Angeles

  1992

• M.S., Electrical Engineering

  University of California, Los Angeles

  1988

• B.S., Electrical Engineering

  University of California, Los Angeles

  1986

Awards & honors

• Fang Lu Endowed Chair in Engineering (2025)
• The Vannevar Bush Faculty Fellow (2021)
• The Brillouin Medal from the International Phononics Society…
• Clarivate Analytics Highly Cited Researcher (2015)
• Fellow of The Materials Research Society (2014)