Welcome to Dr. Aquil Ahmad's Homepage!


       "Next-Gen Spintronics: Quantum Materials to Devices" 



ACADEMIC POSITIONS:


August 2023~ present: NSTC-Postdoctoral Research Fellow

Department of Physics,

National Changhua University of Education, Taiwan

Advisor: Prof. Jyh-Pin Chou  (Associate Professor)


February 2022~July 2023: MOST-Postdoctoral Research Scientist

Department of Physics,

National Changhua University of Education, Taiwan

Advisor: Prof. Chia-Jye Liu (Distinguished Professor)


August 2021-December 2021: Assistant Professor Research 

Department of Physics, 

School of Electrical and Electronics Engineering, 

SASTRA Deemed University, Tamil Nadu India. 


February 2021-August 2021: Research Associate

Department of Physics

Indian Institute of Technology Kharagpur (IIT-Kharagpur)

Advisor: Prof. Amal Kumar Das

Let's change the world together for the better!


"Discovery consists of seeing what everyone has seen, and thinking what no one has thought"- Albert  Szent-Gyorgi (1932 Nobel Laureate) 

“Machine intelligence is the last invention that humanity will ever need to make.” - Nick Bostrom

Supervised by Professors Amal Kumar Das and Sanjeev Kumar Srivastava, my doctoral research at the Indian Institute of Technology Kharagpur (IIT-Kharagpur) focused on the fabrication and characterization of half-metallic nanostructures for spin-driven electronics. In 2021, I worked as a research associate at IIT Kharagpur, followed by an Assistant Professor Research position at SASTRA Deemed University. In 2022, I began my postdoctoral research at National Changhua University of Education (NCUE) in Taiwan, working on thermoelectric materials with Distinguished Prof. C-J Liu. In 2023, I joined my second postdoc at Prof. J-P Chou’s Group of NCUE, studying lattice surfaces and 2D quantum materials for spintronics, and quantum computing.

Research Interests

My research is focused on condensed matter physics, which studies the behavior of matter in its solid and liquid states, employing the principles of quantum mechanics. My research interest lies in experimental investigations of various solid-state systems that exhibit novel properties. These include half metallicity, colossal magnetoresistance (GMR/TMR), superconductivity, topological Weyl semimetals, magnetic skyrmions, AFM spintronics, and qubits.

In condensed matter physics, the examination of solid and liquid states underpins numerous technological advancements and fundamental understandings. Quantum mechanics serves as the theoretical framework guiding the exploration of material properties and phenomena. My research focuses on experimental endeavors, where I investigate a diverse range of nanoscaled systems to unravel their unique electronic, magnetic, and quantum characteristics. 

In addition to experiments, I employ Ab initio-based Density Functional Theory (DFT) computations to deepen our understanding of the fundamental physics underlying these systems. By leveraging computational methods, I delve into the intricacies of material behavior at the atomic and electronic levels, allowing for precise predictions and interpretations. Furthermore, I utilize machine learning algorithms to sift through vast materials databases, extracting meaningful insights and optimizing compositions for enhanced material properties and device performance. This multifaceted approach, combining experimental research with computational modeling and data-driven analyses, enables a comprehensive exploration of condensed matter systems, facilitating both theoretical advancements and practical applications in various fields.

My research focuses on several key areas, including:

“Quantum Materials: The Key to Unlocking Spintronics, Data Storage and Quantum Computing for Next-Generation Information Processing”  

Spintronics: 

Spintronics, unlike traditional electronics, harnesses electron’s spin alongside charge, promising enhanced capabilities and energy efficiency. Recent advances, like increased magnetic data storage, exemplify its potential. Half metallic ferromagnets naturally generate spin-polarized currents. However, the properties crucial for manipulating these currents in spintronics, such as spin coherence, electrostatic screening, and characteristic decay lengths, typically occur at the nanoscale. The movement of spin-polarized currents through a device is intrinsically linked to the material's intricate electronic structure. Remarkably, even basic electrical resistance measurements can provide insights into fundamental quantum mechanical phenomena within these magnetic nanostructures. To effectively study and utilize spin-polarized currents, researchers often fabricate thin-film or multilayer magnetic devices. These magnetic thin films and nanostructures exhibit a fascinating array of unique and intriguing physical properties themselves. My research focuses on nanoscale spintronic device physics, employing magnetic and electrical measurements. Manipulating spin-polarized currents, crucial for spintronics, relies on nanoscale phenomena. Understanding these requires studying intricate electronic structures, even through basic resistance measurements. Thin-film magnetic devices and hybrid structures merging half-metallic magnets with semiconductors (Si, GaAs etc.) offer promising avenues, extending functionalities beyond conventional limits.

Experimental techniques, while essential, face limitations in nanoscale fabrication. Computational methods like Ab initio DFT calculations and machine learning fill this gap. DFT simulations provide insights into spin transport mechanisms, guiding material design, while machine learning aids in data analysis, accelerating material discovery. Combining these approaches enhances understanding and facilitates the development of spintronic technologies.


Defect engineering in Semiconductors for Quantum technologies:

Quantum technology (QT) holds remarkable promise for revolutionizing various fields, including communication, sensing, and computation. However, the current platforms for QT predominantly rely on superconducting materials, which demand cryogenic temperatures and pose scalability challenges. As an alternative, semiconductor-based quantum systems, particularly point defects, emerge as a compelling avenue for advancing quantum device fabrication.

Point defects in semiconductors offer unique quantum properties that make them promising candidates for QT applications. These defects, arising from vacancies, substitutions, or impurities in the crystal lattice, exhibit long coherence times and robust quantum states at ambient temperatures. Leveraging these properties, researchers are exploring various semiconductor materials, such as silicon carbide (SiC) and diamond, to host point defects for quantum functionalities.

The exploration of point defects in semiconductors for QT represents a growing field of research with significant international interest. Researchers are not only striving to understand the fundamental properties of these defects but also working towards engineering scalable quantum devices based on semiconductor platforms. Advances in defect engineering, material synthesis, and device integration are driving the realization of robust and scalable semiconductor quantum technologies.

Selected publications:

1. "Observation of disorder-driven dramatic enhancement of magnetic moment and giant magnetoresistance in a half-metallic Heusler nanoalloy"

       Aquil Ahmad, A.K. Das, S.K. Srivastava, and J. P. Chou (2024) [Under review].

2.  "Investigation of the electronic structure, mechanical and thermoelectric properties of novel semiconductor compounds: XYTe (X=Ti/Sc; Y= Fe/Co)" 

        Aquil Ahmad and Chia-Jyi Liu

        Phys. Chem. Chem. Phys. (2023):  IF: 3.945, Date of publication: 20-05-2023

3. "Giant magnetocaloric effect in Co2FeAl Heusler nanoparticles"

       Aquil Ahmad (Corresponding author), S. Mira, S.K. Srivastava, A.K. Das

       J. Phys. D: Appl. Phys. 54, 385001 (2021); IF: 3.409

4.   "First-principles calculation and experimental studies on Co2FeGe Heusler alloy nanoparticles for spintronics application"

       Aquil Ahmad (Corresponding author), S.K. Srivastava and A.K. Das

       J. Alloys Compounds 878, 160341 (2021); IF: 6.371

5.  "Phase stability and the effect of lattice distortions on electronic properties and half-metallic ferromagnetism of Co2FeAl Heusler alloy: An ab initio study"

      Aquil Ahmad, S.K. Srivastava and A.K. Das

      J. Phys.: Condens. Matter 32, 415606 (2020); IF: 2.745

6.   "A machine learning approach to predict structural and magnetic properties of Heusler alloy families"

        S. Mira, Aquil Ahmad, S. Chakrabarti, and A.K. Das

        Comput. Mater. Sci. 216 (2022) 111836; IF: 3.572.