Despina Louca

Ph.D., 1997, Pennsylvania
Maxine S. and Jesse W. Beams Professor of Physics

Experimental Condensed Matter Physics

dl4f@Virginia.EDU
Office 317 JBL
924-6802

Research Interests

Professor Louca's group studies phase transitions in solids. The group is interested in understanding how the underlying interactions involving the spin, charge and lattice degrees of freedom lead to emergent properties such as polaron formation, Jahn-Teller type distortions, spin and charge density waves, superconductivity and quantum spin liquid states. The most recent systems of interest include topological insulators and semimetals, spintronic antiferromagnets of the I-Mn-V class, transition metal dichalcogenides, disorder superconductors, layered semiconductors etc. These systems have underlying macroscopic functionalities that can potentially lead to industrial applications. The bulk of this research is performed at national and international neutron and X-ray facilities. The group is also involved with materials synthesis and characterization of the bulk properties, performed at the University of Virginia.

Graduate Students

Selected Publications

1. "Metal-insulator transition and doping-induced phase change in Ge2Sb2Se5xTe5-5x", Z. Xu, K. Park, J. A. Schneeloch, and D. Louca, Applied Physics Letters 117, 193503 (2020).
 
2. “Evidence for pseudo–Jahn-Teller distortions in the charge density wave phase of 1T-TiSe2”, A. Wegner, J. Zhao, J. Li, J. Yang, A. A. Anikin, G. Karapetrov, K. Esfarjani, D. Louca, U. Chatterjee”, Phys. Rev. B 101, 195145 (2020).
 
3. "Charge Density Modulation and Defect Ordering in NaMnBi magnetic semimetal", A. Wegner, D. Louca, K. Taddei, J. Neuefeind, D. Louca, Phys. Rev. B 102, 020403(R) (2020).
 
4. "Td to 1T′ structural phase transition in WTe2 Weyl semimetal", Y. Tao, J. A. Schneeloch, A. A. Aczel, and D. Louca, Phys. Rev. B 102, 060103(R) (2020).
 
5. "Evolution of the structural transition in Mo1−xWxTe2", J. A. Schneeloch, Y. Tao, C. Duan, M. Matsuda, A. A. Aczel, J. A. Fernandez-Baca, G. Xu, J. C. Neuefeind, J. Yang and D. Louca, Phys. Rev. B 102, 054105, (2020).
 
6. “Nanoscale Atomic Distortions in the BiS2 Superconductors: Ferrodistortive Sulfur Modes”, A. Athauda and D. Louca, J. Phys. Soc. JPN 88, 041004 (2019).
 
7. “The 9th American Conference on Neutron Scattering”, P. Gehring, A. Hallas, M. Helgeson, B. Josey, D. Louca, K. Page, K. A. Ross, N. Ross, Neutron News 30, 4 (2019).
 
8. “Emergence of topologically protected states in MoTe2 Weyl semimetal with layer stacking order”, J. A. Schneeloch, C. Duan, J. Yang, J. Liu, X. Wang, and D. Louca, Phys. Rev. B. 99, 161105(R) (2019).
 
10. "Appearanc of a Td* phase across the Td to 1T′ phase bounday in the Weyl semimetal MoTe2", Y Tao, JA Schneeloch, C Duan, M Matsuda, SE Dissanayake, AA Aczel, Jaime A Fernandez-Baca, Feng Ye, Despina Louca, Physical Review B 100 (10), 100101 (2019).
 
11. "Electronic band tuning under pressure in MoTe2 topological semimetal", S. Dissanayake, C. Duan, J. Yang, J. Liu, M. Matsuda, C. Yue, J. A Schneeloch, J. C. Y. Teo, D. Louca, NPJ Quantum Materials 4 (2019).
 

12. "Local trigonal modes and the suppression of the charge density wave in TiSe2-xTex", A Wegner, D Louca, J Yang, Physical Review B 99 (20), 205110 (2019).

13.“Emergence of topologically protected states in MoTe2 Weyl semimetal with layer stacking order”, J. A. Schneeloch, C. Duan, J. Yang, J. Liu, X. Wang, and D. Louca, Phys. Rev. B. 99, 161105(R) (2019).

14.“Defect-driven extreme magnetoresistance in an I-Mn-V semiconductor”, J. Yang, A. Wegner, C. M. Brown, and D. Louca, Applied Physics Letters 113, 122105 (2018).     

15. “Appearance of superconductivity at the vacancy order-disorder boundary in KxFe2-ySe2”, C. Duan, J. Yang, Y. Ren, S. M. Thomas and D. Louca, Phys. Rev. B 97, 184502 (2018).    
 
16. “Fe vacancy order and domain distribution in AxFe2-ySe2”, C. Duan and D. Louca, J. Supercond. Novel Magn. 31, 757 (2018).   
 
17.“Elastic and electronic tuning of magnetoresistance in MoTe2”, J. Yang, J. Colen, J. Liu, M. C. Nguyen, G.-W. Chern, and D. Louca, Science Advances 3, No. 12, eaao4949 (2017). 
 

News Items

Despina Louca has been elected to a three-year term on the American Physical Society's Panel on Public Affairs (POPA). POPA is responsible for making recommendations ......More >
Prof. Louca is organizing a 2-day workshop in February 1-2, 2021, on Muon Spin Spectroscopy. The workshop will be virtual  given the ongoing COVID-19 pandemic. The Virtual Muon-2021 ......More >
Despina Louca’s group, and in particular graduate student Aaron Wegner and postdoctoral researcher Junjie Yang, has discovered a way to boost the magnetoresistance in the I-Mn-V class of ......More >
Researchers at UVa found a way through strain engineering to manipulate the electronic band structure, and induce large, reversible response of the magnetoresistive properties under high ......More >
Prof. Despina Louca has been elected to serve a four year term as President of the Neutron Scattering Society of America. See  More >
Dear Colleagues,   Peter Arnold and Despina Louca have been elected 2014 APS Fellows. Please join me to say “congratulations” to these two ......More >
Despina Louca, with her colleagues at UT Austin, received one of the three MIRT awards made by the National Science Foundation this year among high competition.The Materials Interdisciplinary ......More >

Honors

President of the Neutron Scattering Society of America [2017-2020]
APS Fellow [2014]
For demonstration of the importance of the local atomic structure for elucidating the physical properties of complex oxides including the transition metal oxides through neutron scattering using the pair-density-function analysis.