Good day, Gulloo Lal Prajapati. I'm Arjun. I've had a look through your background and your professional record. I'm interested in hearing more about your work and how you see yourself fitting in here with our faculty. Ready to start?

Please start by introducing your professional journey in academia.

Yeah, so I did my.

PhD at Indian institute of science education and research, Bhopal, India. My PhD thesis was thesis title was low energy and ultrafast dynamics of correlated oxides investigated by the rajas spectroscopy. So in my PhD work I mainly studied transition metal oxides using terah spectroscopy as a principle tool.

And studies the material property at Terahash frequency. Subsequently I joined as a postdoc at HELM at Helmholtz in Germany. Here we have a high filter high spectroscopy lab. So here we mainly study Terahash induced property in materials.

Thanks for sharing that!

Professor, let's start with verifying your expertise in Quantum Materials and related areas. Could you explain the role of topological insulators in quantum material research and their potential applications?

Yeah, in topological materials, the bulk state is insulating while the surface state is conducting and.

And uh, it's it's expanded structure near the Dirac point.

Has nearly linear band structure with, uh, with, uh, dim with uh, nearly zero band gap. So surface stress is highly conducting and and uh with using topological materials. For example in.

Data has related application. We can use it for high harmonic generation and in in frequency conversations using topological materials.

Yeah.

Now focusing on the teaching aspect, Professor, how would you explain the concept of quantum entanglement to undergraduate students who are new to quantum mechanics?

Yeah. So I will start as follow.

So it.

Yeah.

If if we talk about any material at the microscopic level, it is consist of eight terms which are periodically arranged within the 8 terms. There are electrons at outer orbitals and electron has spin as well as charge and and orbitals hybridize to make a.

Molecules are compound, so at microscopic level we can describe any any material in any physical property based on how electrons move electrons.

How how how electrons move is being precise, orbitals hybridize and lattice vibrate and how they interact with each other?

So so on.

Yeah, in, in most of the materials. Uh, uh.

The the the fundamental degrees of freedom, that is being lattice charge and orbital degrees of freedoms are coupled. They interact with each other, they affect the, they affect the.

It is at their cell.

Property so that is in enclement.

Got it, Professor. Now let's move to another teaching aspect. How would you design a laboratory experiment to demonstrate superconductivity to postgraduate students?

So I will first, uh.

First, uh, introduce about what is the superconductivity and how what are the main features.

Based on which we can, we can define at the superconductory. For example, superconductors have nearly uh missed it. They are perfect conductor with 0 resistance, but as well as they are perfect tire. Magnetism is inside a material, there is no net magnetic moment, so miss it, it is so much missionary effect. So these two properties are essential to define a superconductivity based on that.

Understood.

Redesign the experiment after describing this concept.

Thank you, Professor. Now focusing on student evaluation, how do you typically design exams to assess both theoretical understanding and practical application of quantum materials concepts?

Yes. So in, in, in my opinion, uh, in, I would like to.

Give give questions which are related to.

To concept so that when when they derive the questions and they solve the numerical problems, their concerts becomes much more clear and then I will give some.

Real world problem related to some real consequences so that they can relate.

It with the theory what they have studied.

Understood, Professor. Transitioning now to guiding student research and projects, could you share an example of how you would steer a student developing a thesis on quantum materials for applications in energy storage systems?

So I will. I will first.

Uh, student that they should first, uh, uh, be clear. What is the quantum mechanics? What are the quantum materials? And they do literature survey. What are the.

Go

Current problems which we need to study and understand then.

Then I will I will, for example, I study at more about transition metal oxides, which are part of quantum materials. I will then instruct them specifically about learning transition metal oxides, what are their fundamental features and what are their fundamental properties. And then I will give specific problems which can be solved using.

Data has a spectroscopy. How the.

How the quantum material property can be investigated using terrazzo spectroscopy, as well as how can how these properties can be manipulated using terahertz pulses?

So this would be the sequence.

Office studying quantum material properties.

Thank

Which I will ask students to follow.

Thank you for the detailed explanation, Professor. Now focusing on communication and teaching approach, how would you simplify a complex quantum mechanics concept, such as tunneling, for students with diverse academic backgrounds?

Yes. So I will start with uh, uh, with classical aspects that in, in classical mechanics, everything is fixed means, uh, everything is certain. If if we talk about uh, uh, an object, so we can define accurately what is its energy, what is its velocity, What is it's, it's, we can define its state accurately 100%, but in quantum.

Even we know accurately what is is energy and momentum, but still we can't define the state of matter appropriately 100%. So there is uncertainty. So miss quantum mechanics is a probabilistic approach.

So, umm.

Can you repeat your question again?

How would you simplify the concept of quantum tunneling for students with diverse academic backgrounds?

OK, thank you so so so I as I was explaining, this is the basic difference between classical mechanics and quantum mechanics. Classical mechanics explains the state of matter.

At 100% surety but quantum mechanics.

Is explains the state of matter with with in terms of probability and then I will give a simple example suppose.

A particle is inside a, uh, square well. So if the energy of the particle is less than the potential well, then classroom can say that, uh, says that uh, uh, particle cannot, uh, go beyond the well.

But, uh, quantum mechanics will tell that they are each certain probability that, uh, particle can pass from the well, it, it can go out of that well. So, so, and, and this probability will depend on the kinetic energy of the particle. So if we give a sufficient kinetic energy and then.

We'll get so much connected energy that at some stage it can.

Then particle.

Uh, pass out from the well that would. That is called tunneling.

Uh, this would be my lesson.

Yeah.

Thank you, Professor. Let’s now discuss your research contributions. Could you describe one of your notable publications related to quantum materials and its impact on this field?

I I I mentioned earlier my research is studying quantum material properties using terahertz spectroscopy as a principal tool. So I use data as radiation to to probe and manipulate the quantum material properties. So my notable studies are are like.

Probing the three and collective charge carrier dynamics in there. As Nicholas, we also developed a new method to probe the electronic page coexistence using Terraz radiation.

As application points, have you considered I we we proposed?

Application of modulators and in recent studies we have shown that that the the high filter high pulses can induce marked insulator metal transition despite the large mud mud compared to the Terahash photon energy and in another example, we for the first time.

So emission of high harmonics upon terahertz excitation in Mart insulators. So these studies missed the last two results, that is the uh.

Actor has induced insulator medical transition and Terra has induced high harmonic generation in Martin insulators where unexpected prior to the experiment because of a large difference between the mod guide and the hydroponic energy, so the source that high filter.

Are capable of.

Thank

Manipulating the material properties which can which may not be expected before the prior to the experiment and and the and. The most important thing is that the data has photon energy.

Terra Husband is a band overlaps with the with the.

With the energy scale of the microscopic interactions present in the quantum materials, so this so this makes that that data has a spectroscopy as an ideal tool to prove and manipulate the quantum material properties.

So these are my contributions in studying quantum material properties.

Thank you, Professor, for elaborating on your research contributions. Now, let’s move towards the last verification aspect: your experience in industry projects or consultancy. Have you contributed to or collaborated on any industry-focused projects or consultancy roles related to quantum materials or their applications?

Yeah. So quantum materials have, uh.

Various industry related applications and my expertise is to slow the quantum material property using Tera radiation in that aspect that Terahatch radiation finds various applications for example in medicals, security, quality assurance, even the proposed 6G technology is based on if we will fully depend on how efficient.

Production of terahertz radiations happen so.

So I so I I said in in my previous study I have already shown that using high filter, high respectroscopy we can induce the marked insulator metal transition and these materials can be used for for example in memoristic device, in modulators and.

Yeah, it it.

Uh.

Again the that again highlights overcomes the thermal effect on quantum nature of the material property.

So that will find find in that will find application in advanced technology. Because in in in in advanced technology we are we want to synthesize a state of matter which could cost low energy and and that kind of work at ultra fast rate and and that is possible using high filter as process.

Understood, Professor. Thank you for providing detailed insights into your industrial perspective. Please hold as we finalize this verification phase.

To begin, Professor, could you share which foundational quantum materials course you most enjoy teaching and why?

So I would.

I would enjoy quantum mechanics.

First course Quantum mechanics First course at an undergraduate level? Because this is directly related to my UH.

Research because because, uh, in In my research, I'm using high filter pulses to explore the quantum material property and their properties are highly based on the principles of quantum mechanics.

So.

I will be suitable in teaching quantum mechanics.

Understood, Professor. Thank you for sharing that.

Professor Prajapati, I noticed your extensive research experience and achievements during your PhD in Physics at IISER Bhopal. I want to focus on your work related to Pulsed Laser Deposition (PLD) for thin films and heterostructures. Could you elaborate on a specific project or study where you utilized PLD extensively? What was the scientific goal, and how did you approach the challenges encountered?

Yes, so, so, uh, in my PhD as well as in my postdoc, I studied the material properties.

In in in their thin film form using Terra hazard spectroscopy. So I mainly studied transition metal oxides. So I prepared thin films of transition metal oxides using first laser deposition technique and in. In thin film you can manipulate the material property by choosing relevant substrates which will.

Which will induce if it takes a strain and and you can also.

Uh, vary the film thin film, uh, thickness as well as you can also vary the oxygen content by controlling the, the deposition pressure during the thin film growth. So based on that, you can, we, you can synthesize the, the material and you can enhance or suppress the property of the material based on your desire.

So, uh.

Yeah, I used Ledger deposition technique to.

I see. It

To optimize the material property or suppressor, enhance the material property, which we are.

Are looking for.

Yeah. So, so if I can give particular example of they are very sensitive to if it takes a strain as well as oxygen stoichiometry. So in case of if it takes a strain, we if we choose the compressive strain, then it will increase the overall metallicity of the film. And if we increase the tensilation and then it will increase the overall insulating nature of the film and it will also. Affect the.

Understood. When using Pulsed Laser Deposition to optimize the material properties of transition metal oxide films, could you share a specific instance where the strain induced by the substrate or oxygen content adjustments had a significant impact on the material's behavior? What were the observed outcomes, and how did they advance your understanding of these materials?

Insulator metal transition temperature. So by choosing this appropriate state where.

We can. We can, uh.

We can induce the insulator metal transition from low temperature to up to room temperature, as well as we can also modulate the sharpness sharpness in the resistivity across the isolated metal transition that can.

And this property can be used for for for example, in, in, in, in, in memory stick device or or in modulation case. Similarly, if we vary the oxygen content, so if if it is oxygen deficient then it will increase the insulating nature of the property and it will also increase the scratching rate between the charge carriers.

So based on that, we can, we can.

That sounds fascinating.

Mark later isolating and metallic property of the rare earth Nicholas.

Thank you for explaining. This demonstrates your deep understanding of how strain and oxygen stoichiometry can be fine-tuned to modify material properties significantly. Beyond your experimental techniques, how do you approach explaining such complex concepts—like strain-induced property changes or insulator-metal transitions—to students, ensuring that they grasp both the physical phenomena and their practical implications?

Yeah, so, so I will explain as follow.

So when we make the thin pill on a substrate single crystal substate then.

There can be two scenario, either the lattice parameter of the substrate is greater than the lattice parameter of the bulk of which we want to make thin film and thin film and in this case in this case.

And in second case, lattice parameter of software can be smaller than the lattice parameter of the bulk. And when we deploy the thin film, the film will always try to attain the in plane lattice parameter of the substrate. So in one case where the substrate lattice parameter is greater than the greater than the deposited, greater than the bulk.

Then the film will try to expand to achieve the latest parameter of the substrate, so it will be stretched. So we define this as a tensile strand in second case when the lattice parameter of the bulk is.

Uh, greater than the underlying such state. Then film will try to compress to achieve the lattice parameter of the substrate.

This will be.

Defined as a compressive strength.

And in case of rare Earth necklace, the stretching and compression both determine the magnitude of hybrid digestion between oxygen and nickel ions. So in case of tensile strength, the the in plane hybridization between oxygen and nickel decreases while the out of plane hybridization between oxygen and nickel decreases.

Because the the the.

Nicolette properties governed by the in plane mostly by the implant hybridization. So decrease in the in plane hybridization increase the insulating nature of the material and in other case intensified sorry in compressive strain where the implant hybridization between nickel and oxygen increases.

Due to compressive strength, it will increase the metallic nature of the matter.

Metal ignition of the field.

Yeah.

Thank you for the thorough explanation, Professor Prajapati. You've demonstrated a clear ability to break down complex phenomena into comprehensible steps. This approach—linking lattice parameters, strain effects, and material properties—seems effective for educating students. Let's proceed.

Professor, could you provide a detailed 3-year roadmap for your research in quantum materials, emphasizing the sustainability of your work in driving institutional rankings and securing external funding?

Yeah. So if I have been given opportunity, I would like to establish high filter hazardous spectroscopy lab to study the quantum materials.

Uh, us only recently people people have succeeded to produce sufficient is sufficient strong terrorist pulses and there are only few left in the world with high filter hygiene spectroscopy lab and none in India. So if I have been given opportunity, I will establish high filtered spectroscopy lab at vit that would be the first of its kind in India.

And and as I explained earlier.

That's a

The the energy scale of microscopic interactions present in quantum materials overlap with the terahertz band, so terahertz. So this makes terah husband a powerful tool to probe and manipulate the material manipulate the properties of quantum materials because the the quantum material property is mainly governed by the microscopic interactions between fundamental degrees of freedom, which we.

And selectively manipulate and probe using terahertz radiation. So I think this will advance the this will contribute significantly in the study of quantum material properties.

Related quantum material, related science and technology and I will to to acquire funding I will write.

Write a funding project, write write a grant proposals which are available at NRF website including the the SRG that is SRG grant which is which is for new faculties and I will also try to collaborate in abroad for example.

My current poster group which is at Helmholtz and understand.

Understood,

So yeah, with that I will try to start my research career.

Understood, Professor. How do you plan to mentor junior students to ensure a consistent pipeline of high-quality publications originating from your proposed lab?

Yeah, so.

So 2.

Yeah, to do the high quality research and and produce a high quality publication, you need to, you need to.

To do the research on on the current research topics so so as I explained so I am currently working in high filter hazard spectroscopy lab Terra hazard spectroscopic field, which has recently only recently started. So there are limited crews so so so using high filter as a spectroscopy whatever materials you use to elaborate that would be novel in itself because.

Most of the metal systems so far have remained unexplored.

Please

Using high filter has a spectroscopy, This will it's this is the novelty and second thing that as I have mentioned that the energy scale of microscopic interactions overlap with the terahertz band. So terahertz radiation is capable of selectively pro manipulating the microscopic interactions, for example, uh, spin charge correlation.

Which in my previous studies I have explained that the screen charge correlation is very sense effects a lot in the high harmonic generation.

So these kind of microscopic interactions are backbone of quantum material properties which we can manipulate. So, so it will it it will create a lot of technological applications once it will it it it has a significance in both exploring fundamental science because if we are managed to if we.

If we are able to manage to control the microscopic interactions, then it will ultimately increase.

Our understanding in fundamental physics and secondly, if we are able to manipulate the microscopic interactions, then that means we will be able to.

Two months later, material properties based on our desire that will increase the technological prospect of the material. So these things.

Will increase the probability of the work to get published in a high impact journal.

Yeah.

How do you plan to utilize international collaborations, such as with your previous research group at Helmholtz, to boost citation metrics and strengthen the global impact of your research in quantum materials?

Yeah. So, so as I said, I will establish high filter Rajesh spectroscopy lab at bit and where I will use tabletop set of two characterize the material properties using terahertz spectroscopy and for advanced characterization I will.

Write the proposal to use the user facility which is available in my current post doc group here which is called Tailway.

So it provides a multi cycle quasi monochromatic frequency to enable terahertz pulses with high reputation rate and high field so so data quality.

With this set of easier coil is a very much superior compared to the data which we obtain using the tabletop setup. So this will enhance the quality of research. Secondly, I also have a theoretical collaborations 11 from my institute which is HDTR itself and 2nd is from University of Rivers, Switzerland. So so I will use theoretical.

Collaboration to understand the.

Property of the material in in detail that will increase the.